From patchwork Mon Nov 4 14:27:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225911 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BE66E1515 for ; Mon, 4 Nov 2019 14:28:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3A71A222C4 for ; Mon, 4 Nov 2019 14:28:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="khHV2SIA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A71A222C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1B34A6B0005; Mon, 4 Nov 2019 09:28:56 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 1893E6B0006; Mon, 4 Nov 2019 09:28:56 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 02BFA6B0008; Mon, 4 Nov 2019 09:28:55 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id D23E36B0005 for ; Mon, 4 Nov 2019 09:28:55 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 7E540180AD820 for ; Mon, 4 Nov 2019 14:28:55 +0000 (UTC) X-FDA: 76118826630.09.rate51_6ad551e803e35 X-Spam-Summary: 10,1,0,23645206f4fcc053,d41d8cd98f00b204,3ozxaxqukcaqipzivksskpi.gsqpmry1-qqozego.svk@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:152:334:355:368:369:379:541:617:960:966:968:973:982:988:989:1260:1277:1313:1314:1345:1359:1431:1437:1516:15 18:1593: X-HE-Tag: rate51_6ad551e803e35 X-Filterd-Recvd-Size: 75154 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:28:54 +0000 (UTC) Received: by mail-wm1-f73.google.com with SMTP id o8so6421562wmc.2 for ; Mon, 04 Nov 2019 06:28:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=W2KMc75T+ey98cQATeXScdAroFGPFLtMgEgekCTGnp4=; b=khHV2SIAKHkd352HaLsUVqwJ92TOqfDzaFA7Hkz00Z0PuPSTF2SuNcIMV6wsPXM0Qi ISIP+PppUWbkHSlCLe+tz++ARU8GPcONVzDvLn2YESUtHaNx79xrQPNlIJvd26CitKh/ m5WOCOmbGjqgYsuilgY58QLUbgrNqxYo2yClwXjBoa3NV+RAo0IDFEGqpcRUYOJJpaNk DUK6KR6zG6Zj02hEaPQ5B5PcTyrQdB/oSOJqmW4jMace+fPLa1KVsDX0ZXsUJ1LOE4bH xSLeuEQ3Dedw5PJHxLHj6iC0FKZ0JILP+Xtv1ruZZsJxmnfyw6ePFHZSZCbSRDhfmEf3 n+Aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=W2KMc75T+ey98cQATeXScdAroFGPFLtMgEgekCTGnp4=; b=h6asIYeRXbtL+5HOxVAn/z52V5+goPDqqUflAb6PZyXelL/Zrszgp3vqFy9H8Bj3vd uagdXX1/L1OUzf8cuQwI789k3aC4h91gtP4ywTRszzQbP4o+K7ZqGG7O7Tkah5Xj70pb PDlFo8bIIROU7sMQunrwjqdAWuzl3ijaFPv7dWbYDWB6Lrqzta/n5Uttop0ZDmXE0O3O bcY5cfXteQ/Xc0/PxQS2ZgycZfBOAngt6gG1b4wcn0kF/GxtHkPtkn+vKE/612T5LlAi ztAdouUq893D3/PQEWjr9ztDNY/1FHiSJ83XfOvo3X4/ALbRvIq4aDyVcdHm+FfyQhZ4 4K5w== X-Gm-Message-State: APjAAAWd8O5QpD00yjzvW2qhEX4YQfXrlFZ3116rBNvaGc7xB6h3Xffz zuKnJz7i2m558kJqnvbAb043rmyuaw== X-Google-Smtp-Source: APXvYqy2MM7n8v3QVs4WzH/3u5Yz2iIYf80J9dFAuV7/VaHSZPbnbfyKTvF5xhiVPcWVcA86l9Y+M0wX5A== X-Received: by 2002:a5d:6585:: with SMTP id q5mr17167512wru.158.1572877731936; Mon, 04 Nov 2019 06:28:51 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:37 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-2-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 1/9] kcsan: Add Kernel Concurrency Sanitizer infrastructure From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Kernel Concurrency Sanitizer (KCSAN) is a dynamic data-race detector for kernel space. KCSAN is a sampling watchpoint-based data-race detector. See the included Documentation/dev-tools/kcsan.rst for more details. This patch adds basic infrastructure, but does not yet enable KCSAN for any architecture. Signed-off-by: Marco Elver --- v3: * Move Documentation to separate patch. * Default init_task 'disable_count' to 0, since kcsan_enabled is sufficient. * Fix CFLAGS for compilers that do not support all options. * lib/Kconfig.kcsan: - Clarify preference of config option over boot param in comment. - Add ref to Documentation - Remove unnecessary "KCSAN:" * include/linux/compiler.h: Remove (const void*) casts * include/linux/kcsan.h: - Reword atomic nestable and flat region comment, and clarify that they are independent. - Rename atomic_region -> atomic_nest_count. - Rename atomic_region_flat -> in_flat_atomic. - Rename kcsan_{begin,end}_atomic -> kcsan_{nestable,flat}_atomic_{begin,end} * kernel/kcsan/kcsan.h: - Capitalize enums. - Make KCSAN_NUM_WATCHPOINTS configurable -> lib/Kconfig.kcsan. * Make kcsan_is_atomic inlinable by turning atomic.c into atomic.h. * kernel/kcsan/core.c (merged with previous kcsan.c): - Make __tsan_unaligned __alias of generic accesses. - user_access_save/restore() usage comment. - Add instruction watchpoint skip randomization. - Refactor API and core runtime fast-path and slow-path; check_access is now the single entry point for checking an access. Compared to the previous version, with a default config and benchmarked using the microbenchmark, this version is 3.8x faster. * kernel/kcsan/test.c: Add more comments where appropriate. * kernel/kcsan/report.c: - get_thread_desc should just return "interrupt" for any interrupt. - increase NUM_STACK_ENTRIES to 64. * kernel/kcsan/debugfs.c - More appropriate error codes. - Use kmalloc+krealloc instead of kvmalloc. - Handle kmalloc failures. - Add debugfs based microbenchmark. * Use '{ }' on same line where appropriate. * Prefer IS_ENABLED instead of #ifdef. * Use common spelling: "data-race" -> "data race" * Other typos. v2: * Elaborate comment about instrumentation calls emitted by compilers. * Replace kcsan_check_access(.., {true, false}) with kcsan_check_{read,write} for improved readability. * Change bug title of race of unknown origin to just say "data-race in". * Refine "Key Properties" in kcsan.rst, and mention observed slow-down. * Add comment about safety of find_watchpoint without user_access_save. * Remove unnecessary preempt_disable/enable and elaborate on comment why we want to disable interrupts and preemptions. * Use common struct kcsan_ctx in task_struct and for per-CPU interrupt contexts [Suggested by Mark Rutland]. --- MAINTAINERS | 11 + Makefile | 3 +- include/linux/compiler-clang.h | 9 + include/linux/compiler-gcc.h | 7 + include/linux/compiler.h | 35 ++- include/linux/kcsan-checks.h | 97 ++++++ include/linux/kcsan.h | 115 +++++++ include/linux/sched.h | 4 + init/init_task.c | 8 + init/main.c | 2 + kernel/Makefile | 1 + kernel/kcsan/Makefile | 11 + kernel/kcsan/atomic.h | 27 ++ kernel/kcsan/core.c | 560 +++++++++++++++++++++++++++++++++ kernel/kcsan/debugfs.c | 275 ++++++++++++++++ kernel/kcsan/encoding.h | 94 ++++++ kernel/kcsan/kcsan.h | 131 ++++++++ kernel/kcsan/report.c | 306 ++++++++++++++++++ kernel/kcsan/test.c | 121 +++++++ lib/Kconfig.debug | 2 + lib/Kconfig.kcsan | 119 +++++++ lib/Makefile | 3 + scripts/Makefile.kcsan | 6 + scripts/Makefile.lib | 10 + 24 files changed, 1948 insertions(+), 9 deletions(-) create mode 100644 include/linux/kcsan-checks.h create mode 100644 include/linux/kcsan.h create mode 100644 kernel/kcsan/Makefile create mode 100644 kernel/kcsan/atomic.h create mode 100644 kernel/kcsan/core.c create mode 100644 kernel/kcsan/debugfs.c create mode 100644 kernel/kcsan/encoding.h create mode 100644 kernel/kcsan/kcsan.h create mode 100644 kernel/kcsan/report.c create mode 100644 kernel/kcsan/test.c create mode 100644 lib/Kconfig.kcsan create mode 100644 scripts/Makefile.kcsan diff --git a/MAINTAINERS b/MAINTAINERS index cba1095547fd..ac9cceb6a8ae 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8848,6 +8848,17 @@ F: Documentation/kbuild/kconfig* F: scripts/kconfig/ F: scripts/Kconfig.include +KCSAN +M: Marco Elver +R: Dmitry Vyukov +L: kasan-dev@googlegroups.com +S: Maintained +F: Documentation/dev-tools/kcsan.rst +F: include/linux/kcsan*.h +F: kernel/kcsan/ +F: lib/Kconfig.kcsan +F: scripts/Makefile.kcsan + KDUMP M: Dave Young M: Baoquan He diff --git a/Makefile b/Makefile index b37d0e8fc61d..79154b0b69db 100644 --- a/Makefile +++ b/Makefile @@ -478,7 +478,7 @@ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE -export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN CFLAGS_KCSAN export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL @@ -900,6 +900,7 @@ endif include scripts/Makefile.kasan include scripts/Makefile.extrawarn include scripts/Makefile.ubsan +include scripts/Makefile.kcsan # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments KBUILD_CPPFLAGS += $(KCPPFLAGS) diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 333a6695a918..a213eb55e725 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -24,6 +24,15 @@ #define __no_sanitize_address #endif +#if __has_feature(thread_sanitizer) +/* emulate gcc's __SANITIZE_THREAD__ flag */ +#define __SANITIZE_THREAD__ +#define __no_sanitize_thread \ + __attribute__((no_sanitize("thread"))) +#else +#define __no_sanitize_thread +#endif + /* * Not all versions of clang implement the the type-generic versions * of the builtin overflow checkers. Fortunately, clang implements diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index d7ee4c6bad48..de105ca29282 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -145,6 +145,13 @@ #define __no_sanitize_address #endif +#if __has_attribute(__no_sanitize_thread__) && defined(__SANITIZE_THREAD__) +#define __no_sanitize_thread \ + __attribute__((__noinline__)) __attribute__((no_sanitize_thread)) +#else +#define __no_sanitize_thread +#endif + #if GCC_VERSION >= 50100 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 5e88e7e33abe..0b6506b9dd11 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -178,6 +178,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, #endif #include +#include #define __READ_ONCE_SIZE \ ({ \ @@ -193,12 +194,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, } \ }) -static __always_inline -void __read_once_size(const volatile void *p, void *res, int size) -{ - __READ_ONCE_SIZE; -} - #ifdef CONFIG_KASAN /* * We can't declare function 'inline' because __no_sanitize_address confilcts @@ -211,14 +206,38 @@ void __read_once_size(const volatile void *p, void *res, int size) # define __no_kasan_or_inline __always_inline #endif -static __no_kasan_or_inline +#ifdef CONFIG_KCSAN +# define __no_kcsan_or_inline __no_sanitize_thread notrace __maybe_unused +#else +# define __no_kcsan_or_inline __always_inline +#endif + +#if defined(CONFIG_KASAN) || defined(CONFIG_KCSAN) +/* Avoid any instrumentation or inline. */ +#define __no_sanitize_or_inline \ + __no_sanitize_address __no_sanitize_thread notrace __maybe_unused +#else +#define __no_sanitize_or_inline __always_inline +#endif + +static __no_kcsan_or_inline +void __read_once_size(const volatile void *p, void *res, int size) +{ + kcsan_check_atomic_read(p, size); + __READ_ONCE_SIZE; +} + +static __no_sanitize_or_inline void __read_once_size_nocheck(const volatile void *p, void *res, int size) { __READ_ONCE_SIZE; } -static __always_inline void __write_once_size(volatile void *p, void *res, int size) +static __no_kcsan_or_inline +void __write_once_size(volatile void *p, void *res, int size) { + kcsan_check_atomic_write(p, size); + switch (size) { case 1: *(volatile __u8 *)p = *(__u8 *)res; break; case 2: *(volatile __u16 *)p = *(__u16 *)res; break; diff --git a/include/linux/kcsan-checks.h b/include/linux/kcsan-checks.h new file mode 100644 index 000000000000..e78220661086 --- /dev/null +++ b/include/linux/kcsan-checks.h @@ -0,0 +1,97 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_KCSAN_CHECKS_H +#define _LINUX_KCSAN_CHECKS_H + +#include + +/* + * Access type modifiers. + */ +#define KCSAN_ACCESS_WRITE 0x1 +#define KCSAN_ACCESS_ATOMIC 0x2 + +/* + * __kcsan_*: Always calls into runtime when KCSAN is enabled. This may be used + * even in compilation units that selectively disable KCSAN, but must use KCSAN + * to validate access to an address. Never use these in header files! + */ +#ifdef CONFIG_KCSAN +/** + * __kcsan_check_access - check generic access for data race + * + * @ptr address of access + * @size size of access + * @type access type modifier + */ +void __kcsan_check_access(const volatile void *ptr, size_t size, int type); + +#else +static inline void __kcsan_check_access(const volatile void *ptr, size_t size, + int type) { } +#endif + +/* + * kcsan_*: Only calls into runtime when the particular compilation unit has + * KCSAN instrumentation enabled. May be used in header files. + */ +#ifdef __SANITIZE_THREAD__ +#define kcsan_check_access __kcsan_check_access +#else +static inline void kcsan_check_access(const volatile void *ptr, size_t size, + int type) { } +#endif + +/** + * __kcsan_check_read - check regular read access for data races + * + * @ptr address of access + * @size size of access + */ +#define __kcsan_check_read(ptr, size) __kcsan_check_access(ptr, size, 0) + +/** + * __kcsan_check_write - check regular write access for data races + * + * @ptr address of access + * @size size of access + */ +#define __kcsan_check_write(ptr, size) \ + __kcsan_check_access(ptr, size, KCSAN_ACCESS_WRITE) + +/** + * kcsan_check_read - check regular read access for data races + * + * @ptr address of access + * @size size of access + */ +#define kcsan_check_read(ptr, size) kcsan_check_access(ptr, size, 0) + +/** + * kcsan_check_write - check regular write access for data races + * + * @ptr address of access + * @size size of access + */ +#define kcsan_check_write(ptr, size) \ + kcsan_check_access(ptr, size, KCSAN_ACCESS_WRITE) + +/* + * Check for atomic accesses: if atomic access are not ignored, this simply + * aliases to kcsan_check_access, otherwise becomes a no-op. + */ +#ifdef CONFIG_KCSAN_IGNORE_ATOMICS +#define kcsan_check_atomic_read(...) \ + do { \ + } while (0) +#define kcsan_check_atomic_write(...) \ + do { \ + } while (0) +#else +#define kcsan_check_atomic_read(ptr, size) \ + kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC) +#define kcsan_check_atomic_write(ptr, size) \ + kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC | KCSAN_ACCESS_WRITE) +#endif + +#endif /* _LINUX_KCSAN_CHECKS_H */ diff --git a/include/linux/kcsan.h b/include/linux/kcsan.h new file mode 100644 index 000000000000..bd8122acae01 --- /dev/null +++ b/include/linux/kcsan.h @@ -0,0 +1,115 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_KCSAN_H +#define _LINUX_KCSAN_H + +#include +#include + +#ifdef CONFIG_KCSAN + +/* + * Context for each thread of execution: for tasks, this is stored in + * task_struct, and interrupts access internal per-CPU storage. + */ +struct kcsan_ctx { + int disable_count; /* disable counter */ + int atomic_next; /* number of following atomic ops */ + + /* + * We distinguish between: (a) nestable atomic regions that may contain + * other nestable regions; and (b) flat atomic regions that do not keep + * track of nesting. Both (a) and (b) are entirely independent of each + * other, and a flat region may be started in a nestable region or + * vice-versa. + * + * This is required because, for example, in the annotations for + * seqlocks, we declare seqlock writer critical sections as (a) nestable + * atomic regions, but reader critical sections as (b) flat atomic + * regions, but have encountered cases where seqlock reader critical + * sections are contained within writer critical sections (the opposite + * may be possible, too). + * + * To support these cases, we independently track the depth of nesting + * for (a), and whether the leaf level is flat for (b). + */ + int atomic_nest_count; + bool in_flat_atomic; +}; + +/** + * kcsan_init - initialize KCSAN runtime + */ +void kcsan_init(void); + +/** + * kcsan_disable_current - disable KCSAN for the current context + * + * Supports nesting. + */ +void kcsan_disable_current(void); + +/** + * kcsan_enable_current - re-enable KCSAN for the current context + * + * Supports nesting. + */ +void kcsan_enable_current(void); + +/** + * kcsan_nestable_atomic_begin - begin nestable atomic region + * + * Accesses within the atomic region may appear to race with other accesses but + * should be considered atomic. + */ +void kcsan_nestable_atomic_begin(void); + +/** + * kcsan_nestable_atomic_end - end nestable atomic region + */ +void kcsan_nestable_atomic_end(void); + +/** + * kcsan_flat_atomic_begin - begin flat atomic region + * + * Accesses within the atomic region may appear to race with other accesses but + * should be considered atomic. + */ +void kcsan_flat_atomic_begin(void); + +/** + * kcsan_flat_atomic_end - end flat atomic region + */ +void kcsan_flat_atomic_end(void); + +/** + * kcsan_atomic_next - consider following accesses as atomic + * + * Force treating the next n memory accesses for the current context as atomic + * operations. + * + * @n number of following memory accesses to treat as atomic. + */ +void kcsan_atomic_next(int n); + +#else /* CONFIG_KCSAN */ + +static inline void kcsan_init(void) { } + +static inline void kcsan_disable_current(void) { } + +static inline void kcsan_enable_current(void) { } + +static inline void kcsan_nestable_atomic_begin(void) { } + +static inline void kcsan_nestable_atomic_end(void) { } + +static inline void kcsan_flat_atomic_begin(void) { } + +static inline void kcsan_flat_atomic_end(void) { } + +static inline void kcsan_atomic_next(int n) { } + +#endif /* CONFIG_KCSAN */ + +#endif /* _LINUX_KCSAN_H */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 67a1d86981a9..ae4f341c1db4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -31,6 +31,7 @@ #include #include #include +#include /* task_struct member predeclarations (sorted alphabetically): */ struct audit_context; @@ -1172,6 +1173,9 @@ struct task_struct { #ifdef CONFIG_KASAN unsigned int kasan_depth; #endif +#ifdef CONFIG_KCSAN + struct kcsan_ctx kcsan_ctx; +#endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* Index of current stored address in ret_stack: */ diff --git a/init/init_task.c b/init/init_task.c index 9e5cbe5eab7b..2b4fe98b0f09 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -161,6 +161,14 @@ struct task_struct init_task #ifdef CONFIG_KASAN .kasan_depth = 1, #endif +#ifdef CONFIG_KCSAN + .kcsan_ctx = { + .disable_count = 0, + .atomic_next = 0, + .atomic_nest_count = 0, + .in_flat_atomic = false, + }, +#endif #ifdef CONFIG_TRACE_IRQFLAGS .softirqs_enabled = 1, #endif diff --git a/init/main.c b/init/main.c index 91f6ebb30ef0..4d814de017ee 100644 --- a/init/main.c +++ b/init/main.c @@ -93,6 +93,7 @@ #include #include #include +#include #include #include @@ -779,6 +780,7 @@ asmlinkage __visible void __init start_kernel(void) acpi_subsystem_init(); arch_post_acpi_subsys_init(); sfi_init_late(); + kcsan_init(); /* Do the rest non-__init'ed, we're now alive */ arch_call_rest_init(); diff --git a/kernel/Makefile b/kernel/Makefile index daad787fb795..74ab46e2ebd1 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -102,6 +102,7 @@ obj-$(CONFIG_TRACEPOINTS) += trace/ obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-$(CONFIG_CPU_PM) += cpu_pm.o obj-$(CONFIG_BPF) += bpf/ +obj-$(CONFIG_KCSAN) += kcsan/ obj-$(CONFIG_PERF_EVENTS) += events/ diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile new file mode 100644 index 000000000000..dd15b62ec0b5 --- /dev/null +++ b/kernel/kcsan/Makefile @@ -0,0 +1,11 @@ +# SPDX-License-Identifier: GPL-2.0 +KCSAN_SANITIZE := n +KCOV_INSTRUMENT := n + +CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE) + +CFLAGS_core.o := $(call cc-option,-fno-conserve-stack,) \ + $(call cc-option,-fno-stack-protector,) + +obj-y := core.o debugfs.o report.o +obj-$(CONFIG_KCSAN_SELFTEST) += test.o diff --git a/kernel/kcsan/atomic.h b/kernel/kcsan/atomic.h new file mode 100644 index 000000000000..c9c3fe628011 --- /dev/null +++ b/kernel/kcsan/atomic.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _KERNEL_KCSAN_ATOMIC_H +#define _KERNEL_KCSAN_ATOMIC_H + +#include + +/* + * Helper that returns true if access to ptr should be considered as an atomic + * access, even though it is not explicitly atomic. + * + * List all volatile globals that have been observed in races, to suppress + * data race reports between accesses to these variables. + * + * For now, we assume that volatile accesses of globals are as strong as atomic + * accesses (READ_ONCE, WRITE_ONCE cast to volatile). The situation is still not + * entirely clear, as on some architectures (Alpha) READ_ONCE/WRITE_ONCE do more + * than cast to volatile. Eventually, we hope to be able to remove this + * function. + */ +static inline bool kcsan_is_atomic(const volatile void *ptr) +{ + /* only jiffies for now */ + return ptr == &jiffies; +} + +#endif /* _KERNEL_KCSAN_ATOMIC_H */ diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c new file mode 100644 index 000000000000..3755f09acf17 --- /dev/null +++ b/kernel/kcsan/core.c @@ -0,0 +1,560 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kcsan.h" +#include "atomic.h" +#include "encoding.h" + +/* + * Helper macros to iterate slots, starting from address slot itself, followed + * by the right and left slots. + */ +#define CHECK_NUM_SLOTS (1 + 2 * KCSAN_CHECK_ADJACENT) +#define SLOT_IDX(slot, i) \ + ((slot + (((i + KCSAN_CHECK_ADJACENT) % CHECK_NUM_SLOTS) - \ + KCSAN_CHECK_ADJACENT)) % \ + CONFIG_KCSAN_NUM_WATCHPOINTS) + +bool kcsan_enabled; + +/* Per-CPU kcsan_ctx for interrupts */ +static DEFINE_PER_CPU(struct kcsan_ctx, kcsan_cpu_ctx) = { + .disable_count = 0, + .atomic_next = 0, + .atomic_nest_count = 0, + .in_flat_atomic = false, +}; + +/* + * Watchpoints, with each entry encoded as defined in encoding.h: in order to be + * able to safely update and access a watchpoint without introducing locking + * overhead, we encode each watchpoint as a single atomic long. The initial + * zero-initialized state matches INVALID_WATCHPOINT. + */ +static atomic_long_t watchpoints[CONFIG_KCSAN_NUM_WATCHPOINTS]; + +/* + * Instructions to skip watching counter, used in should_watch(). We use a + * per-CPU counter to avoid excessive contention. + */ +static DEFINE_PER_CPU(long, kcsan_skip); + +static inline atomic_long_t *find_watchpoint(unsigned long addr, size_t size, + bool expect_write, + long *encoded_watchpoint) +{ + const int slot = watchpoint_slot(addr); + const unsigned long addr_masked = addr & WATCHPOINT_ADDR_MASK; + atomic_long_t *watchpoint; + unsigned long wp_addr_masked; + size_t wp_size; + bool is_write; + int i; + + BUILD_BUG_ON(CONFIG_KCSAN_NUM_WATCHPOINTS < CHECK_NUM_SLOTS); + + for (i = 0; i < CHECK_NUM_SLOTS; ++i) { + watchpoint = &watchpoints[SLOT_IDX(slot, i)]; + *encoded_watchpoint = atomic_long_read(watchpoint); + if (!decode_watchpoint(*encoded_watchpoint, &wp_addr_masked, + &wp_size, &is_write)) + continue; + + if (expect_write && !is_write) + continue; + + /* Check if the watchpoint matches the access. */ + if (matching_access(wp_addr_masked, wp_size, addr_masked, size)) + return watchpoint; + } + + return NULL; +} + +static inline atomic_long_t *insert_watchpoint(unsigned long addr, size_t size, + bool is_write) +{ + const int slot = watchpoint_slot(addr); + const long encoded_watchpoint = encode_watchpoint(addr, size, is_write); + atomic_long_t *watchpoint; + int i; + + for (i = 0; i < CHECK_NUM_SLOTS; ++i) { + long expect_val = INVALID_WATCHPOINT; + + /* Try to acquire this slot. */ + watchpoint = &watchpoints[SLOT_IDX(slot, i)]; + if (atomic_long_try_cmpxchg_relaxed(watchpoint, &expect_val, + encoded_watchpoint)) + return watchpoint; + } + + return NULL; +} + +/* + * Return true if watchpoint was successfully consumed, false otherwise. + * + * This may return false if: + * + * 1. another thread already consumed the watchpoint; + * 2. the thread that set up the watchpoint already removed it; + * 3. the watchpoint was removed and then re-used. + */ +static inline bool try_consume_watchpoint(atomic_long_t *watchpoint, + long encoded_watchpoint) +{ + return atomic_long_try_cmpxchg_relaxed(watchpoint, &encoded_watchpoint, + CONSUMED_WATCHPOINT); +} + +/* + * Return true if watchpoint was not touched, false if consumed. + */ +static inline bool remove_watchpoint(atomic_long_t *watchpoint) +{ + return atomic_long_xchg_relaxed(watchpoint, INVALID_WATCHPOINT) != + CONSUMED_WATCHPOINT; +} + +static inline struct kcsan_ctx *get_ctx(void) +{ + /* + * In interrupt, use raw_cpu_ptr to avoid unnecessary checks, that would + * also result in calls that generate warnings in uaccess regions. + */ + return in_task() ? ¤t->kcsan_ctx : raw_cpu_ptr(&kcsan_cpu_ctx); +} + +static inline bool is_atomic(const volatile void *ptr) +{ + struct kcsan_ctx *ctx = get_ctx(); + + if (unlikely(ctx->atomic_next > 0)) { + --ctx->atomic_next; + return true; + } + if (unlikely(ctx->atomic_nest_count > 0 || ctx->in_flat_atomic)) + return true; + + return kcsan_is_atomic(ptr); +} + +static inline bool should_watch(const volatile void *ptr, int type) +{ + /* + * Never set up watchpoints when memory operations are atomic. + * + * Need to check this first, before kcsan_skip check below: (1) atomics + * should not count towards skipped instructions, and (2) to actually + * decrement kcsan_atomic_next for consecutive instruction stream. + */ + if ((type & KCSAN_ACCESS_ATOMIC) != 0 || is_atomic(ptr)) + return false; + + if (this_cpu_dec_return(kcsan_skip) >= 0) + return false; + + /* avoid underflow if !kcsan_is_enabled() */ + this_cpu_write(kcsan_skip, -1); + + /* this operation should be watched */ + return true; +} + +static inline void reset_kcsan_skip(void) +{ + long skip_count = CONFIG_KCSAN_SKIP_WATCH - + (IS_ENABLED(CONFIG_KCSAN_SKIP_WATCH_RANDOMIZE) ? + prandom_u32_max(CONFIG_KCSAN_SKIP_WATCH) : + 0); + this_cpu_write(kcsan_skip, skip_count); +} + +static inline bool kcsan_is_enabled(void) +{ + return READ_ONCE(kcsan_enabled) && get_ctx()->disable_count == 0; +} + +static inline unsigned int get_delay(void) +{ + unsigned int delay = in_task() ? CONFIG_KCSAN_UDELAY_TASK : + CONFIG_KCSAN_UDELAY_INTERRUPT; + return delay - (IS_ENABLED(CONFIG_KCSAN_DELAY_RANDOMIZE) ? + prandom_u32_max(delay) : + 0); +} + +/* + * Pull everything together: check_access() below contains the performance + * critical operations; the fast-path (including check_access) functions should + * all be inlinable by the instrumentation functions. + * + * The slow-path (kcsan_found_watchpoint, kcsan_setup_watchpoint) are + * non-inlinable -- note that, we prefix these with "kcsan_" to ensure they can + * be filtered from the stacktrace, as well as give them unique names for the + * UACCESS whitelist of objtool. Each function uses user_access_save/restore(), + * since they do not access any user memory, but instrumentation is still + * emitted in UACCESS regions. + */ + +static noinline void kcsan_found_watchpoint(const volatile void *ptr, + size_t size, bool is_write, + bool consumed) +{ + unsigned long flags = user_access_save(); + enum kcsan_report_type report_type; + + if (!consumed) { + /* + * The other thread may not print any diagnostics, as it has + * already removed the watchpoint, or another thread consumed + * the watchpoint before this thread. + */ + kcsan_counter_inc(KCSAN_COUNTER_REPORT_RACES); + report_type = KCSAN_REPORT_RACE_CHECK_RACE; + } else { + report_type = KCSAN_REPORT_RACE_CHECK; + } + + kcsan_counter_inc(KCSAN_COUNTER_DATA_RACES); + kcsan_report(ptr, size, is_write, raw_smp_processor_id(), report_type); + + user_access_restore(flags); +} + +static noinline void kcsan_setup_watchpoint(const volatile void *ptr, + size_t size, bool is_write) +{ + atomic_long_t *watchpoint; + union { + u8 _1; + u16 _2; + u32 _4; + u64 _8; + } expect_value; + bool is_expected = true; + unsigned long ua_flags = user_access_save(); + unsigned long irq_flags; + + if (!check_encodable((unsigned long)ptr, size)) { + kcsan_counter_inc(KCSAN_COUNTER_UNENCODABLE_ACCESSES); + goto out; + } + + /* + * Disable interrupts & preemptions to avoid another thread on the same + * CPU accessing memory locations for the set up watchpoint; this is to + * avoid reporting races to e.g. CPU-local data. + * + * An alternative would be adding the source CPU to the watchpoint + * encoding, and checking that watchpoint-CPU != this-CPU. There are + * several problems with this: + * 1. we should avoid stealing more bits from the watchpoint encoding + * as it would affect accuracy, as well as increase performance + * overhead in the fast-path; + * 2. if we are preempted, but there *is* a genuine data race, we + * would *not* report it -- since this is the common case (vs. + * CPU-local data accesses), it makes more sense (from a data race + * detection point of view) to simply disable preemptions to ensure + * as many tasks as possible run on other CPUs. + */ + local_irq_save(irq_flags); + + watchpoint = insert_watchpoint((unsigned long)ptr, size, is_write); + if (watchpoint == NULL) { + /* + * Out of capacity: the size of `watchpoints`, and the frequency + * with which `should_watch()` returns true should be tweaked so + * that this case happens very rarely. + */ + kcsan_counter_inc(KCSAN_COUNTER_NO_CAPACITY); + goto out_unlock; + } + + /* + * Reset kcsan_skip counter: only do this if we succeeded in setting up + * a watchpoint. + */ + reset_kcsan_skip(); + + kcsan_counter_inc(KCSAN_COUNTER_SETUP_WATCHPOINTS); + kcsan_counter_inc(KCSAN_COUNTER_USED_WATCHPOINTS); + + /* + * Read the current value, to later check and infer a race if the data + * was modified via a non-instrumented access, e.g. from a device. + */ + switch (size) { + case 1: + expect_value._1 = READ_ONCE(*(const u8 *)ptr); + break; + case 2: + expect_value._2 = READ_ONCE(*(const u16 *)ptr); + break; + case 4: + expect_value._4 = READ_ONCE(*(const u32 *)ptr); + break; + case 8: + expect_value._8 = READ_ONCE(*(const u64 *)ptr); + break; + default: + break; /* ignore; we do not diff the values */ + } + + if (IS_ENABLED(CONFIG_KCSAN_DEBUG)) { + kcsan_disable_current(); + pr_err("KCSAN: watching %s, size: %zu, addr: %px [slot: %d, encoded: %lx]\n", + is_write ? "write" : "read", size, ptr, + watchpoint_slot((unsigned long)ptr), + encode_watchpoint((unsigned long)ptr, size, is_write)); + kcsan_enable_current(); + } + + /* + * Delay this thread, to increase probability of observing a racy + * conflicting access. + */ + udelay(get_delay()); + + /* + * Re-read value, and check if it is as expected; if not, we infer a + * racy access. + */ + switch (size) { + case 1: + is_expected = expect_value._1 == READ_ONCE(*(const u8 *)ptr); + break; + case 2: + is_expected = expect_value._2 == READ_ONCE(*(const u16 *)ptr); + break; + case 4: + is_expected = expect_value._4 == READ_ONCE(*(const u32 *)ptr); + break; + case 8: + is_expected = expect_value._8 == READ_ONCE(*(const u64 *)ptr); + break; + default: + break; /* ignore; we do not diff the values */ + } + + /* Check if this access raced with another. */ + if (!remove_watchpoint(watchpoint)) { + /* + * No need to increment 'data_races' counter, as the racing + * thread already did. + */ + kcsan_report(ptr, size, is_write, smp_processor_id(), + KCSAN_REPORT_RACE_SETUP); + } else if (!is_expected) { + /* Inferring a race, since the value should not have changed. */ + kcsan_counter_inc(KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN); + if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN)) + kcsan_report(ptr, size, is_write, smp_processor_id(), + KCSAN_REPORT_RACE_UNKNOWN_ORIGIN); + } + + kcsan_counter_dec(KCSAN_COUNTER_USED_WATCHPOINTS); +out_unlock: + local_irq_restore(irq_flags); +out: + user_access_restore(ua_flags); +} + +static inline void check_access(const volatile void *ptr, size_t size, int type) +{ + const bool is_write = (type & KCSAN_ACCESS_WRITE) != 0; + atomic_long_t *watchpoint; + long encoded_watchpoint; + + if (IS_ENABLED(CONFIG_KCSAN_PLAIN_WRITE_PRETEND_ONCE) && is_write) + type |= KCSAN_ACCESS_ATOMIC; + + /* + * Avoid user_access_save in fast-path: find_watchpoint is safe without + * user_access_save, as the address that ptr points to is only used to + * check if a watchpoint exists; ptr is never dereferenced. + */ + watchpoint = find_watchpoint((unsigned long)ptr, size, !is_write, + &encoded_watchpoint); + + /* + * It is safe to check kcsan_is_enabled() after find_watchpoint, but + * right before we would enter the slow-path: no state changes that + * cause a data race to be detected and reported have occurred yet. + */ + + if (unlikely(watchpoint != NULL) && kcsan_is_enabled()) { + /* + * Try consume the watchpoint as soon after finding the + * watchpoint as possible; this must always be guarded by + * kcsan_is_enabled() check, as otherwise we might erroneously + * triggering reports when disabled. + */ + const bool consumed = + try_consume_watchpoint(watchpoint, encoded_watchpoint); + + kcsan_found_watchpoint(ptr, size, is_write, consumed); + } else if (unlikely(should_watch(ptr, type)) && kcsan_is_enabled()) { + kcsan_setup_watchpoint(ptr, size, is_write); + } +} + +/* === Public interface ===================================================== */ + +void __init kcsan_init(void) +{ + BUG_ON(!in_task()); + + kcsan_debugfs_init(); + + /* + * We are in the init task, and no other tasks should be running; + * WRITE_ONCE without memory barrier is sufficient. + */ + if (IS_ENABLED(CONFIG_KCSAN_EARLY_ENABLE)) + WRITE_ONCE(kcsan_enabled, true); +} + +/* === Exported interface =================================================== */ + +void kcsan_disable_current(void) +{ + ++get_ctx()->disable_count; +} +EXPORT_SYMBOL(kcsan_disable_current); + +void kcsan_enable_current(void) +{ + if (get_ctx()->disable_count-- == 0) { + kcsan_disable_current(); /* restore to 0 */ + kcsan_disable_current(); + WARN(1, "mismatching %s", __func__); + kcsan_enable_current(); + } +} +EXPORT_SYMBOL(kcsan_enable_current); + +void kcsan_nestable_atomic_begin(void) +{ + /* + * Do *not* check and warn if we are in a flat atomic region: nestable + * and flat atomic regions are independent from each other. + * See include/linux/kcsan.h: struct kcsan_ctx comments for more + * comments. + */ + + ++get_ctx()->atomic_nest_count; +} +EXPORT_SYMBOL(kcsan_nestable_atomic_begin); + +void kcsan_nestable_atomic_end(void) +{ + if (get_ctx()->atomic_nest_count-- == 0) { + kcsan_nestable_atomic_begin(); /* restore to 0 */ + kcsan_disable_current(); + WARN(1, "mismatching %s", __func__); + kcsan_enable_current(); + } +} +EXPORT_SYMBOL(kcsan_nestable_atomic_end); + +void kcsan_flat_atomic_begin(void) +{ + get_ctx()->in_flat_atomic = true; +} +EXPORT_SYMBOL(kcsan_flat_atomic_begin); + +void kcsan_flat_atomic_end(void) +{ + get_ctx()->in_flat_atomic = false; +} +EXPORT_SYMBOL(kcsan_flat_atomic_end); + +void kcsan_atomic_next(int n) +{ + get_ctx()->atomic_next = n; +} +EXPORT_SYMBOL(kcsan_atomic_next); + +void __kcsan_check_access(const volatile void *ptr, size_t size, int type) +{ + check_access(ptr, size, type); +} +EXPORT_SYMBOL(__kcsan_check_access); + +/* + * KCSAN uses the same instrumentation that is emitted by supported compilers + * for ThreadSanitizer (TSAN). + * + * When enabled, the compiler emits instrumentation calls (the functions + * prefixed with "__tsan" below) for all loads and stores that it generated; + * inline asm is not instrumented. + * + * Note that, not all supported compiler versions distinguish aligned/unaligned + * accesses, but e.g. recent versions of Clang do. We simply alias the unaligned + * version to the generic version, which can handle both. + */ + +#define DEFINE_TSAN_READ_WRITE(size) \ + void __tsan_read##size(void *ptr) \ + { \ + check_access(ptr, size, 0); \ + } \ + EXPORT_SYMBOL(__tsan_read##size); \ + void __tsan_unaligned_read##size(void *ptr) \ + __alias(__tsan_read##size); \ + EXPORT_SYMBOL(__tsan_unaligned_read##size); \ + void __tsan_write##size(void *ptr) \ + { \ + check_access(ptr, size, KCSAN_ACCESS_WRITE); \ + } \ + EXPORT_SYMBOL(__tsan_write##size); \ + void __tsan_unaligned_write##size(void *ptr) \ + __alias(__tsan_write##size); \ + EXPORT_SYMBOL(__tsan_unaligned_write##size) + +DEFINE_TSAN_READ_WRITE(1); +DEFINE_TSAN_READ_WRITE(2); +DEFINE_TSAN_READ_WRITE(4); +DEFINE_TSAN_READ_WRITE(8); +DEFINE_TSAN_READ_WRITE(16); + +void __tsan_read_range(void *ptr, size_t size) +{ + check_access(ptr, size, 0); +} +EXPORT_SYMBOL(__tsan_read_range); + +void __tsan_write_range(void *ptr, size_t size) +{ + check_access(ptr, size, KCSAN_ACCESS_WRITE); +} +EXPORT_SYMBOL(__tsan_write_range); + +/* + * The below are not required by KCSAN, but can still be emitted by the + * compiler. + */ +void __tsan_func_entry(void *call_pc) +{ +} +EXPORT_SYMBOL(__tsan_func_entry); +void __tsan_func_exit(void) +{ +} +EXPORT_SYMBOL(__tsan_func_exit); +void __tsan_init(void) +{ +} +EXPORT_SYMBOL(__tsan_init); diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c new file mode 100644 index 000000000000..8f1403085032 --- /dev/null +++ b/kernel/kcsan/debugfs.c @@ -0,0 +1,275 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kcsan.h" + +/* + * Statistics counters. + */ +static atomic_long_t counters[KCSAN_COUNTER_COUNT]; + +/* + * Addresses for filtering functions from reporting. This list can be used as a + * whitelist or blacklist. + */ +static struct { + unsigned long *addrs; /* array of addresses */ + size_t size; /* current size */ + int used; /* number of elements used */ + bool sorted; /* if elements are sorted */ + bool whitelist; /* if list is a blacklist or whitelist */ +} report_filterlist = { + .addrs = NULL, + .size = 8, /* small initial size */ + .used = 0, + .sorted = false, + .whitelist = false, /* default is blacklist */ +}; +static DEFINE_SPINLOCK(report_filterlist_lock); + +static const char *counter_to_name(enum kcsan_counter_id id) +{ + switch (id) { + case KCSAN_COUNTER_USED_WATCHPOINTS: + return "used_watchpoints"; + case KCSAN_COUNTER_SETUP_WATCHPOINTS: + return "setup_watchpoints"; + case KCSAN_COUNTER_DATA_RACES: + return "data_races"; + case KCSAN_COUNTER_NO_CAPACITY: + return "no_capacity"; + case KCSAN_COUNTER_REPORT_RACES: + return "report_races"; + case KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN: + return "races_unknown_origin"; + case KCSAN_COUNTER_UNENCODABLE_ACCESSES: + return "unencodable_accesses"; + case KCSAN_COUNTER_ENCODING_FALSE_POSITIVES: + return "encoding_false_positives"; + case KCSAN_COUNTER_COUNT: + BUG(); + } + return NULL; +} + +void kcsan_counter_inc(enum kcsan_counter_id id) +{ + atomic_long_inc(&counters[id]); +} + +void kcsan_counter_dec(enum kcsan_counter_id id) +{ + atomic_long_dec(&counters[id]); +} + +/* + * The microbenchmark allows benchmarking KCSAN core runtime only. To run + * multiple threads, pipe 'microbench=' from multiple tasks into the + * debugfs file. + */ +static void microbenchmark(unsigned long iters) +{ + cycles_t cycles; + + pr_info("KCSAN: %s begin | iters: %lu\n", __func__, iters); + + cycles = get_cycles(); + while (iters--) { + /* + * We can run this benchmark from multiple tasks; this address + * calculation increases likelyhood of some accesses overlapping + * (they still won't conflict because all are reads). + */ + unsigned long addr = + iters % (CONFIG_KCSAN_NUM_WATCHPOINTS * PAGE_SIZE); + __kcsan_check_read((void *)addr, sizeof(long)); + } + cycles = get_cycles() - cycles; + + pr_info("KCSAN: %s end | cycles: %llu\n", __func__, cycles); +} + +static int cmp_filterlist_addrs(const void *rhs, const void *lhs) +{ + const unsigned long a = *(const unsigned long *)rhs; + const unsigned long b = *(const unsigned long *)lhs; + + return a < b ? -1 : a == b ? 0 : 1; +} + +bool kcsan_skip_report(unsigned long func_addr) +{ + unsigned long symbolsize, offset; + unsigned long flags; + bool ret = false; + + if (!kallsyms_lookup_size_offset(func_addr, &symbolsize, &offset)) + return false; + func_addr -= offset; /* get function start */ + + spin_lock_irqsave(&report_filterlist_lock, flags); + if (report_filterlist.used == 0) + goto out; + + /* Sort array if it is unsorted, and then do a binary search. */ + if (!report_filterlist.sorted) { + sort(report_filterlist.addrs, report_filterlist.used, + sizeof(unsigned long), cmp_filterlist_addrs, NULL); + report_filterlist.sorted = true; + } + ret = !!bsearch(&func_addr, report_filterlist.addrs, + report_filterlist.used, sizeof(unsigned long), + cmp_filterlist_addrs); + if (report_filterlist.whitelist) + ret = !ret; + +out: + spin_unlock_irqrestore(&report_filterlist_lock, flags); + return ret; +} + +static void set_report_filterlist_whitelist(bool whitelist) +{ + unsigned long flags; + + spin_lock_irqsave(&report_filterlist_lock, flags); + report_filterlist.whitelist = whitelist; + spin_unlock_irqrestore(&report_filterlist_lock, flags); +} + +/* Returns 0 on success, error-code otherwise. */ +static ssize_t insert_report_filterlist(const char *func) +{ + unsigned long flags; + unsigned long addr = kallsyms_lookup_name(func); + ssize_t ret = 0; + + if (!addr) { + pr_err("KCSAN: could not find function: '%s'\n", func); + return -ENOENT; + } + + spin_lock_irqsave(&report_filterlist_lock, flags); + + if (report_filterlist.addrs == NULL) { + /* initial allocation */ + report_filterlist.addrs = + kmalloc_array(report_filterlist.size, + sizeof(unsigned long), GFP_KERNEL); + if (report_filterlist.addrs == NULL) { + ret = -ENOMEM; + goto out; + } + } else if (report_filterlist.used == report_filterlist.size) { + /* resize filterlist */ + size_t new_size = report_filterlist.size * 2; + unsigned long *new_addrs = + krealloc(report_filterlist.addrs, + new_size * sizeof(unsigned long), GFP_KERNEL); + + if (new_addrs == NULL) { + /* leave filterlist itself untouched */ + ret = -ENOMEM; + goto out; + } + + report_filterlist.size = new_size; + report_filterlist.addrs = new_addrs; + } + + /* Note: deduplicating should be done in userspace. */ + report_filterlist.addrs[report_filterlist.used++] = + kallsyms_lookup_name(func); + report_filterlist.sorted = false; + +out: + spin_unlock_irqrestore(&report_filterlist_lock, flags); + return ret; +} + +static int show_info(struct seq_file *file, void *v) +{ + int i; + unsigned long flags; + + /* show stats */ + seq_printf(file, "enabled: %i\n", READ_ONCE(kcsan_enabled)); + for (i = 0; i < KCSAN_COUNTER_COUNT; ++i) + seq_printf(file, "%s: %ld\n", counter_to_name(i), + atomic_long_read(&counters[i])); + + /* show filter functions, and filter type */ + spin_lock_irqsave(&report_filterlist_lock, flags); + seq_printf(file, "\n%s functions: %s\n", + report_filterlist.whitelist ? "whitelisted" : "blacklisted", + report_filterlist.used == 0 ? "none" : ""); + for (i = 0; i < report_filterlist.used; ++i) + seq_printf(file, " %ps\n", (void *)report_filterlist.addrs[i]); + spin_unlock_irqrestore(&report_filterlist_lock, flags); + + return 0; +} + +static int debugfs_open(struct inode *inode, struct file *file) +{ + return single_open(file, show_info, NULL); +} + +static ssize_t debugfs_write(struct file *file, const char __user *buf, + size_t count, loff_t *off) +{ + char kbuf[KSYM_NAME_LEN]; + char *arg; + int read_len = count < (sizeof(kbuf) - 1) ? count : (sizeof(kbuf) - 1); + + if (copy_from_user(kbuf, buf, read_len)) + return -EFAULT; + kbuf[read_len] = '\0'; + arg = strstrip(kbuf); + + if (!strcmp(arg, "on")) { + WRITE_ONCE(kcsan_enabled, true); + } else if (!strcmp(arg, "off")) { + WRITE_ONCE(kcsan_enabled, false); + } else if (!strncmp(arg, "microbench=", sizeof("microbench=") - 1)) { + unsigned long iters; + + if (kstrtoul(&arg[sizeof("microbench=") - 1], 0, &iters)) + return -EINVAL; + microbenchmark(iters); + } else if (!strcmp(arg, "whitelist")) { + set_report_filterlist_whitelist(true); + } else if (!strcmp(arg, "blacklist")) { + set_report_filterlist_whitelist(false); + } else if (arg[0] == '!') { + ssize_t ret = insert_report_filterlist(&arg[1]); + + if (ret < 0) + return ret; + } else { + return -EINVAL; + } + + return count; +} + +static const struct file_operations debugfs_ops = { .read = seq_read, + .open = debugfs_open, + .write = debugfs_write, + .release = single_release }; + +void __init kcsan_debugfs_init(void) +{ + debugfs_create_file("kcsan", 0644, NULL, NULL, &debugfs_ops); +} diff --git a/kernel/kcsan/encoding.h b/kernel/kcsan/encoding.h new file mode 100644 index 000000000000..e17bdac0e54b --- /dev/null +++ b/kernel/kcsan/encoding.h @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _KERNEL_KCSAN_ENCODING_H +#define _KERNEL_KCSAN_ENCODING_H + +#include +#include +#include + +#include "kcsan.h" + +#define SLOT_RANGE PAGE_SIZE +#define INVALID_WATCHPOINT 0 +#define CONSUMED_WATCHPOINT 1 + +/* + * The maximum useful size of accesses for which we set up watchpoints is the + * max range of slots we check on an access. + */ +#define MAX_ENCODABLE_SIZE (SLOT_RANGE * (1 + KCSAN_CHECK_ADJACENT)) + +/* + * Number of bits we use to store size info. + */ +#define WATCHPOINT_SIZE_BITS bits_per(MAX_ENCODABLE_SIZE) +/* + * This encoding for addresses discards the upper (1 for is-write + SIZE_BITS); + * however, most 64-bit architectures do not use the full 64-bit address space. + * Also, in order for a false positive to be observable 2 things need to happen: + * + * 1. different addresses but with the same encoded address race; + * 2. and both map onto the same watchpoint slots; + * + * Both these are assumed to be very unlikely. However, in case it still happens + * happens, the report logic will filter out the false positive (see report.c). + */ +#define WATCHPOINT_ADDR_BITS (BITS_PER_LONG - 1 - WATCHPOINT_SIZE_BITS) + +/* + * Masks to set/retrieve the encoded data. + */ +#define WATCHPOINT_WRITE_MASK BIT(BITS_PER_LONG - 1) +#define WATCHPOINT_SIZE_MASK \ + GENMASK(BITS_PER_LONG - 2, BITS_PER_LONG - 2 - WATCHPOINT_SIZE_BITS) +#define WATCHPOINT_ADDR_MASK \ + GENMASK(BITS_PER_LONG - 3 - WATCHPOINT_SIZE_BITS, 0) + +static inline bool check_encodable(unsigned long addr, size_t size) +{ + return size <= MAX_ENCODABLE_SIZE; +} + +static inline long encode_watchpoint(unsigned long addr, size_t size, + bool is_write) +{ + return (long)((is_write ? WATCHPOINT_WRITE_MASK : 0) | + (size << WATCHPOINT_ADDR_BITS) | + (addr & WATCHPOINT_ADDR_MASK)); +} + +static inline bool decode_watchpoint(long watchpoint, + unsigned long *addr_masked, size_t *size, + bool *is_write) +{ + if (watchpoint == INVALID_WATCHPOINT || + watchpoint == CONSUMED_WATCHPOINT) + return false; + + *addr_masked = (unsigned long)watchpoint & WATCHPOINT_ADDR_MASK; + *size = ((unsigned long)watchpoint & WATCHPOINT_SIZE_MASK) >> + WATCHPOINT_ADDR_BITS; + *is_write = !!((unsigned long)watchpoint & WATCHPOINT_WRITE_MASK); + + return true; +} + +/* + * Return watchpoint slot for an address. + */ +static inline int watchpoint_slot(unsigned long addr) +{ + return (addr / PAGE_SIZE) % CONFIG_KCSAN_NUM_WATCHPOINTS; +} + +static inline bool matching_access(unsigned long addr1, size_t size1, + unsigned long addr2, size_t size2) +{ + unsigned long end_range1 = addr1 + size1 - 1; + unsigned long end_range2 = addr2 + size2 - 1; + + return addr1 <= end_range2 && addr2 <= end_range1; +} + +#endif /* _KERNEL_KCSAN_ENCODING_H */ diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h new file mode 100644 index 000000000000..f35f71e124c7 --- /dev/null +++ b/kernel/kcsan/kcsan.h @@ -0,0 +1,131 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * The Kernel Concurrency Sanitizer (KCSAN) infrastructure. For more info please + * see Documentation/dev-tools/kcsan.rst. + */ + +#ifndef _KERNEL_KCSAN_KCSAN_H +#define _KERNEL_KCSAN_KCSAN_H + +#include + +/* + * The number of adjacent watchpoints to check; the purpose is 2-fold: + * + * 1. the address slot is already occupied, check if any adjacent slots are + * free; + * 2. accesses that straddle a slot boundary due to size that exceeds a + * slot's range may check adjacent slots if any watchpoint matches. + * + * Note that accesses with very large size may still miss a watchpoint; however, + * given this should be rare, this is a reasonable trade-off to make, since this + * will avoid: + * + * 1. excessive contention between watchpoint checks and setup; + * 2. larger number of simultaneous watchpoints without sacrificing + * performance. + */ +#define KCSAN_CHECK_ADJACENT 1 + +/* + * Globally enable and disable KCSAN. + */ +extern bool kcsan_enabled; + +/* + * Initialize debugfs file. + */ +void kcsan_debugfs_init(void); + +enum kcsan_counter_id { + /* + * Number of watchpoints currently in use. + */ + KCSAN_COUNTER_USED_WATCHPOINTS, + + /* + * Total number of watchpoints set up. + */ + KCSAN_COUNTER_SETUP_WATCHPOINTS, + + /* + * Total number of data races. + */ + KCSAN_COUNTER_DATA_RACES, + + /* + * Number of times no watchpoints were available. + */ + KCSAN_COUNTER_NO_CAPACITY, + + /* + * A thread checking a watchpoint raced with another checking thread; + * only one will be reported. + */ + KCSAN_COUNTER_REPORT_RACES, + + /* + * Observed data value change, but writer thread unknown. + */ + KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN, + + /* + * The access cannot be encoded to a valid watchpoint. + */ + KCSAN_COUNTER_UNENCODABLE_ACCESSES, + + /* + * Watchpoint encoding caused a watchpoint to fire on mismatching + * accesses. + */ + KCSAN_COUNTER_ENCODING_FALSE_POSITIVES, + + KCSAN_COUNTER_COUNT, /* number of counters */ +}; + +/* + * Increment/decrement counter with given id; avoid calling these in fast-path. + */ +void kcsan_counter_inc(enum kcsan_counter_id id); +void kcsan_counter_dec(enum kcsan_counter_id id); + +/* + * Returns true if data races in the function symbol that maps to func_addr + * (offsets are ignored) should *not* be reported. + */ +bool kcsan_skip_report(unsigned long func_addr); + +enum kcsan_report_type { + /* + * The thread that set up the watchpoint and briefly stalled was + * signalled that another thread triggered the watchpoint, and thus a + * race was encountered. + */ + KCSAN_REPORT_RACE_SETUP, + + /* + * A thread encountered a watchpoint for the access, therefore a race + * was encountered. + */ + KCSAN_REPORT_RACE_CHECK, + + /* + * A thread encountered a watchpoint for the access, but the other + * racing thread can no longer be signaled that a race occurred. + */ + KCSAN_REPORT_RACE_CHECK_RACE, + + /* + * No other thread was observed to race with the access, but the data + * value before and after the stall differs. + */ + KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, +}; +/* + * Print a race report from thread that encountered the race. + */ +void kcsan_report(const volatile void *ptr, size_t size, bool is_write, + int cpu_id, enum kcsan_report_type type); + +#endif /* _KERNEL_KCSAN_KCSAN_H */ diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c new file mode 100644 index 000000000000..6c37b0c1c6da --- /dev/null +++ b/kernel/kcsan/report.c @@ -0,0 +1,306 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include + +#include "kcsan.h" +#include "encoding.h" + +/* + * Max. number of stack entries to show in the report. + */ +#define NUM_STACK_ENTRIES 64 + +/* + * Other thread info: communicated from other racing thread to thread that set + * up the watchpoint, which then prints the complete report atomically. Only + * need one struct, as all threads should to be serialized regardless to print + * the reports, with reporting being in the slow-path. + */ +static struct { + const volatile void *ptr; + size_t size; + bool is_write; + int task_pid; + int cpu_id; + unsigned long stack_entries[NUM_STACK_ENTRIES]; + int num_stack_entries; +} other_info = { .ptr = NULL }; + +static DEFINE_SPINLOCK(other_info_lock); +static DEFINE_SPINLOCK(report_lock); + +static bool set_or_lock_other_info(unsigned long *flags, + const volatile void *ptr, size_t size, + bool is_write, int cpu_id, + enum kcsan_report_type type) +{ + if (type != KCSAN_REPORT_RACE_CHECK && type != KCSAN_REPORT_RACE_SETUP) + return true; + + for (;;) { + spin_lock_irqsave(&other_info_lock, *flags); + + switch (type) { + case KCSAN_REPORT_RACE_CHECK: + if (other_info.ptr != NULL) { + /* still in use, retry */ + break; + } + other_info.ptr = ptr; + other_info.size = size; + other_info.is_write = is_write; + other_info.task_pid = + in_task() ? task_pid_nr(current) : -1; + other_info.cpu_id = cpu_id; + other_info.num_stack_entries = stack_trace_save( + other_info.stack_entries, NUM_STACK_ENTRIES, 1); + /* + * other_info may now be consumed by thread we raced + * with. + */ + spin_unlock_irqrestore(&other_info_lock, *flags); + return false; + + case KCSAN_REPORT_RACE_SETUP: + if (other_info.ptr == NULL) + break; /* no data available yet, retry */ + + /* + * First check if matching based on how watchpoint was + * encoded. + */ + if (!matching_access((unsigned long)other_info.ptr & + WATCHPOINT_ADDR_MASK, + other_info.size, + (unsigned long)ptr & + WATCHPOINT_ADDR_MASK, + size)) + break; /* mismatching access, retry */ + + if (!matching_access((unsigned long)other_info.ptr, + other_info.size, + (unsigned long)ptr, size)) { + /* + * If the actual accesses to not match, this was + * a false positive due to watchpoint encoding. + */ + other_info.ptr = NULL; /* mark for reuse */ + kcsan_counter_inc( + KCSAN_COUNTER_ENCODING_FALSE_POSITIVES); + spin_unlock_irqrestore(&other_info_lock, + *flags); + return false; + } + + /* + * Matching access: keep other_info locked, as this + * thread uses it to print the full report; unlocked in + * end_report. + */ + return true; + + default: + BUG(); + } + + spin_unlock_irqrestore(&other_info_lock, *flags); + } +} + +static void start_report(unsigned long *flags, enum kcsan_report_type type) +{ + switch (type) { + case KCSAN_REPORT_RACE_SETUP: + /* irqsaved already via other_info_lock */ + spin_lock(&report_lock); + break; + + case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: + spin_lock_irqsave(&report_lock, *flags); + break; + + default: + BUG(); + } +} + +static void end_report(unsigned long *flags, enum kcsan_report_type type) +{ + switch (type) { + case KCSAN_REPORT_RACE_SETUP: + other_info.ptr = NULL; /* mark for reuse */ + spin_unlock(&report_lock); + spin_unlock_irqrestore(&other_info_lock, *flags); + break; + + case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: + spin_unlock_irqrestore(&report_lock, *flags); + break; + + default: + BUG(); + } +} + +static const char *get_access_type(bool is_write) +{ + return is_write ? "write" : "read"; +} + +/* Return thread description: in task or interrupt. */ +static const char *get_thread_desc(int task_id) +{ + if (task_id != -1) { + static char buf[32]; /* safe: protected by report_lock */ + + snprintf(buf, sizeof(buf), "task %i", task_id); + return buf; + } + return "interrupt"; +} + +/* Helper to skip KCSAN-related functions in stack-trace. */ +static int get_stack_skipnr(unsigned long stack_entries[], int num_entries) +{ + char buf[64]; + int skip = 0; + + for (; skip < num_entries; ++skip) { + snprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skip]); + if (!strnstr(buf, "csan_", sizeof(buf)) && + !strnstr(buf, "tsan_", sizeof(buf)) && + !strnstr(buf, "_once_size", sizeof(buf))) { + break; + } + } + return skip; +} + +/* Compares symbolized strings of addr1 and addr2. */ +static int sym_strcmp(void *addr1, void *addr2) +{ + char buf1[64]; + char buf2[64]; + + snprintf(buf1, sizeof(buf1), "%pS", addr1); + snprintf(buf2, sizeof(buf2), "%pS", addr2); + return strncmp(buf1, buf2, sizeof(buf1)); +} + +/* + * Returns true if a report was generated, false otherwise. + */ +static bool print_summary(const volatile void *ptr, size_t size, bool is_write, + int cpu_id, enum kcsan_report_type type) +{ + unsigned long stack_entries[NUM_STACK_ENTRIES] = { 0 }; + int num_stack_entries = + stack_trace_save(stack_entries, NUM_STACK_ENTRIES, 1); + int skipnr = get_stack_skipnr(stack_entries, num_stack_entries); + int other_skipnr; + + /* Check if the top stackframe is in a blacklisted function. */ + if (kcsan_skip_report(stack_entries[skipnr])) + return false; + if (type == KCSAN_REPORT_RACE_SETUP) { + other_skipnr = get_stack_skipnr(other_info.stack_entries, + other_info.num_stack_entries); + if (kcsan_skip_report(other_info.stack_entries[other_skipnr])) + return false; + } + + /* Print report header. */ + pr_err("==================================================================\n"); + switch (type) { + case KCSAN_REPORT_RACE_SETUP: { + void *this_fn = (void *)stack_entries[skipnr]; + void *other_fn = (void *)other_info.stack_entries[other_skipnr]; + int cmp; + + /* + * Order functions lexographically for consistent bug titles. + * Do not print offset of functions to keep title short. + */ + cmp = sym_strcmp(other_fn, this_fn); + pr_err("BUG: KCSAN: data-race in %ps / %ps\n", + cmp < 0 ? other_fn : this_fn, + cmp < 0 ? this_fn : other_fn); + } break; + + case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: + pr_err("BUG: KCSAN: data-race in %pS\n", + (void *)stack_entries[skipnr]); + break; + + default: + BUG(); + } + + pr_err("\n"); + + /* Print information about the racing accesses. */ + switch (type) { + case KCSAN_REPORT_RACE_SETUP: + pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n", + get_access_type(other_info.is_write), other_info.ptr, + other_info.size, get_thread_desc(other_info.task_pid), + other_info.cpu_id); + + /* Print the other thread's stack trace. */ + stack_trace_print(other_info.stack_entries + other_skipnr, + other_info.num_stack_entries - other_skipnr, + 0); + + pr_err("\n"); + pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n", + get_access_type(is_write), ptr, size, + get_thread_desc(in_task() ? task_pid_nr(current) : -1), + cpu_id); + break; + + case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: + pr_err("race at unknown origin, with %s to 0x%px of %zu bytes by %s on cpu %i:\n", + get_access_type(is_write), ptr, size, + get_thread_desc(in_task() ? task_pid_nr(current) : -1), + cpu_id); + break; + + default: + BUG(); + } + /* Print stack trace of this thread. */ + stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, + 0); + + /* Print report footer. */ + pr_err("\n"); + pr_err("Reported by Kernel Concurrency Sanitizer on:\n"); + dump_stack_print_info(KERN_DEFAULT); + pr_err("==================================================================\n"); + + return true; +} + +void kcsan_report(const volatile void *ptr, size_t size, bool is_write, + int cpu_id, enum kcsan_report_type type) +{ + unsigned long flags = 0; + + if (type == KCSAN_REPORT_RACE_CHECK_RACE) + return; + + kcsan_disable_current(); + if (set_or_lock_other_info(&flags, ptr, size, is_write, cpu_id, type)) { + start_report(&flags, type); + if (print_summary(ptr, size, is_write, cpu_id, type) && + panic_on_warn) + panic("panic_on_warn set ...\n"); + end_report(&flags, type); + } + kcsan_enable_current(); +} diff --git a/kernel/kcsan/test.c b/kernel/kcsan/test.c new file mode 100644 index 000000000000..0bae63c5ca65 --- /dev/null +++ b/kernel/kcsan/test.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include + +#include "encoding.h" + +#define ITERS_PER_TEST 2000 + +/* Test requirements. */ +static bool test_requires(void) +{ + /* random should be initialized for the below tests */ + return prandom_u32() + prandom_u32() != 0; +} + +/* + * Test watchpoint encode and decode: check that encoding some access's info, + * and then subsequent decode preserves the access's info. + */ +static bool test_encode_decode(void) +{ + int i; + + for (i = 0; i < ITERS_PER_TEST; ++i) { + size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1; + bool is_write = !!prandom_u32_max(2); + unsigned long addr; + + prandom_bytes(&addr, sizeof(addr)); + if (WARN_ON(!check_encodable(addr, size))) + return false; + + /* encode and decode */ + { + const long encoded_watchpoint = + encode_watchpoint(addr, size, is_write); + unsigned long verif_masked_addr; + size_t verif_size; + bool verif_is_write; + + /* check special watchpoints */ + if (WARN_ON(decode_watchpoint( + INVALID_WATCHPOINT, &verif_masked_addr, + &verif_size, &verif_is_write))) + return false; + if (WARN_ON(decode_watchpoint( + CONSUMED_WATCHPOINT, &verif_masked_addr, + &verif_size, &verif_is_write))) + return false; + + /* check decoding watchpoint returns same data */ + if (WARN_ON(!decode_watchpoint( + encoded_watchpoint, &verif_masked_addr, + &verif_size, &verif_is_write))) + return false; + if (WARN_ON(verif_masked_addr != + (addr & WATCHPOINT_ADDR_MASK))) + goto fail; + if (WARN_ON(verif_size != size)) + goto fail; + if (WARN_ON(is_write != verif_is_write)) + goto fail; + + continue; +fail: + pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n", + __func__, is_write ? "write" : "read", size, + addr, encoded_watchpoint, + verif_is_write ? "write" : "read", verif_size, + verif_masked_addr); + return false; + } + } + + return true; +} + +/* Test access matching function. */ +static bool test_matching_access(void) +{ + if (WARN_ON(!matching_access(10, 1, 10, 1))) + return false; + if (WARN_ON(!matching_access(10, 2, 11, 1))) + return false; + if (WARN_ON(!matching_access(10, 1, 9, 2))) + return false; + if (WARN_ON(matching_access(10, 1, 11, 1))) + return false; + if (WARN_ON(matching_access(9, 1, 10, 1))) + return false; + return true; +} + +static int __init kcsan_selftest(void) +{ + int passed = 0; + int total = 0; + +#define RUN_TEST(do_test) \ + do { \ + ++total; \ + if (do_test()) \ + ++passed; \ + else \ + pr_err("KCSAN selftest: " #do_test " failed"); \ + } while (0) + + RUN_TEST(test_requires); + RUN_TEST(test_encode_decode); + RUN_TEST(test_matching_access); + + pr_info("KCSAN selftest: %d/%d tests passed\n", passed, total); + if (passed != total) + panic("KCSAN selftests failed"); + return 0; +} +postcore_initcall(kcsan_selftest); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 93d97f9b0157..35accd1d93de 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2086,6 +2086,8 @@ source "lib/Kconfig.kgdb" source "lib/Kconfig.ubsan" +source "lib/Kconfig.kcsan" + config ARCH_HAS_DEVMEM_IS_ALLOWED bool diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan new file mode 100644 index 000000000000..ffe83a79cfe6 --- /dev/null +++ b/lib/Kconfig.kcsan @@ -0,0 +1,119 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config HAVE_ARCH_KCSAN + bool + +menuconfig KCSAN + bool "KCSAN: watchpoint-based dynamic data race detector" + depends on HAVE_ARCH_KCSAN && !KASAN && STACKTRACE + default n + help + Kernel Concurrency Sanitizer is a dynamic data race detector, which + uses a watchpoint-based sampling approach to detect races. See + for more details. + +if KCSAN + +config KCSAN_DEBUG + bool "Debugging of KCSAN internals" + default n + +config KCSAN_SELFTEST + bool "Perform short selftests on boot" + default y + help + Run KCSAN selftests on boot. On test failure, causes kernel to panic. + +config KCSAN_EARLY_ENABLE + bool "Early enable during boot" + default y + help + If KCSAN should be enabled globally as soon as possible. KCSAN can + later be enabled/disabled via debugfs. + +config KCSAN_NUM_WATCHPOINTS + int "Number of available watchpoints" + default 64 + help + Total number of available watchpoints. An address range maps into a + specific watchpoint slot as specified in kernel/kcsan/encoding.h. + Although larger number of watchpoints may not be usable due to + limited number of CPUs, a larger value helps to improve performance + due to reducing cache-line contention. The chosen default is a + conservative value; we should almost never observe "no_capacity" + events (see /sys/kernel/debug/kcsan). + +config KCSAN_UDELAY_TASK + int "Delay in microseconds (for tasks)" + default 80 + help + For tasks, the microsecond delay after setting up a watchpoint. + +config KCSAN_UDELAY_INTERRUPT + int "Delay in microseconds (for interrupts)" + default 20 + help + For interrupts, the microsecond delay after setting up a watchpoint. + Interrupts have tighter latency requirements, and their delay should + be lower than for tasks. + +config KCSAN_DELAY_RANDOMIZE + bool "Randomize above delays" + default y + help + If delays should be randomized, where the maximum is KCSAN_UDELAY_*. + If false, the chosen delays are always KCSAN_UDELAY_* defined above. + +config KCSAN_SKIP_WATCH + int "Skip instructions before setting up watchpoint" + default 4000 + help + The number of per-CPU memory operations to skip, before another + watchpoint is set up, i.e. one in KCSAN_WATCH_SKIP per-CPU + memory operations are used to set up a watchpoint. A smaller value + results in more aggressive race detection, whereas a larger value + improves system performance at the cost of missing some races. + +config KCSAN_SKIP_WATCH_RANDOMIZE + bool "Randomize watchpoint instruction skip count" + default y + help + If instruction skip count should be randomized, where the maximum is + KCSAN_WATCH_SKIP. If false, the chosen value is always + KCSAN_WATCH_SKIP. + +# Note that, while some of the below options could be turned into boot +# parameters, to optimize for the common use-case, we avoid this because: +# (a) it would impact performance (and we want to avoid static branch for all +# {READ,WRITE}_ONCE, atomic_*, bitops, etc.), and (b) complicate the design +# without real benefit. The main purpose of the below options are for use in +# fuzzer configs to control initially reported data races, and are not expected +# to be switched frequently by a user. Finally, since the below options hide +# data races, they should eventually be removed entirely! + +config KCSAN_REPORT_RACE_UNKNOWN_ORIGIN + bool "Report races of unknown origin" + default y + help + If KCSAN should report races where only one access is known, and the + conflicting access is of unknown origin. This type of race is + reported if it was only possible to infer a race due to a data-value + change while an access is being delayed on a watchpoint. + +config KCSAN_IGNORE_ATOMICS + bool "Do not instrument marked atomic accesses" + default n + help + If enabled, never instruments marked atomic accesses. This results in + not reporting data races where one access is atomic and the other is + a plain access. + +config KCSAN_PLAIN_WRITE_PRETEND_ONCE + bool "Pretend plain writes are WRITE_ONCE" + default n + help + This option makes KCSAN pretend that all plain writes are WRITE_ONCE. + This option should only be used to prune initial data races found in + existing code. + +endif # KCSAN diff --git a/lib/Makefile b/lib/Makefile index c5892807e06f..778ab704e3ad 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -24,6 +24,9 @@ KASAN_SANITIZE_string.o := n CFLAGS_string.o := $(call cc-option, -fno-stack-protector) endif +# Used by KCSAN while enabled, avoid recursion. +KCSAN_SANITIZE_random32.o := n + lib-y := ctype.o string.o vsprintf.o cmdline.o \ rbtree.o radix-tree.o timerqueue.o xarray.o \ idr.o extable.o \ diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan new file mode 100644 index 000000000000..caf1111a28ae --- /dev/null +++ b/scripts/Makefile.kcsan @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 +ifdef CONFIG_KCSAN + +CFLAGS_KCSAN := -fsanitize=thread + +endif # CONFIG_KCSAN diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 179d55af5852..8952f909f7c9 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -152,6 +152,16 @@ _c_flags += $(if $(patsubst n%,, \ $(CFLAGS_KCOV)) endif +# +# Enable KCSAN flags except some files or directories we don't want to check +# (depends on variables KCSAN_SANITIZE_obj.o, KCSAN_SANITIZE) +# +ifeq ($(CONFIG_KCSAN),y) +_c_flags += $(if $(patsubst n%,, \ + $(KCSAN_SANITIZE_$(basetarget).o)$(KCSAN_SANITIZE)y), \ + $(CFLAGS_KCSAN)) +endif + # $(srctree)/$(src) for including checkin headers from generated source files # $(objtree)/$(obj) for including generated headers from checkin source files ifeq ($(KBUILD_EXTMOD),) From patchwork Mon Nov 4 14:27:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225913 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7D8F41390 for ; Mon, 4 Nov 2019 14:29:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 30901222D4 for ; Mon, 4 Nov 2019 14:29:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="oRFcJg08" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 30901222D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 88F1B6B0006; Mon, 4 Nov 2019 09:28:57 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 869596B0008; Mon, 4 Nov 2019 09:28:57 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 757F36B000A; Mon, 4 Nov 2019 09:28:57 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0085.hostedemail.com [216.40.44.85]) by kanga.kvack.org (Postfix) with ESMTP id 607FE6B0006 for ; Mon, 4 Nov 2019 09:28:57 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 1DFE32DFC for ; Mon, 4 Nov 2019 14:28:57 +0000 (UTC) X-FDA: 76118826714.03.cap62_6b3068ee08d08 X-Spam-Summary: 2,0,0,fe732ca67385f64a,d41d8cd98f00b204,3pzxaxqukcagmt3mzowwotm.kwutqv25-uus3iks.wzo@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:1:41:69:152:355:379:541:800:960:966:967:973:988:989:1260:1263:1277:1313:1314:1345:1359:1437:1516:1518:1593:1 594:1605 X-HE-Tag: cap62_6b3068ee08d08 X-Filterd-Recvd-Size: 13974 Received: from mail-ua1-f74.google.com (mail-ua1-f74.google.com [209.85.222.74]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:28:56 +0000 (UTC) Received: by mail-ua1-f74.google.com with SMTP id b12so2661650uan.10 for ; Mon, 04 Nov 2019 06:28:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Lk5vY/CQimKOqdkXmX9OcpY1/cmQPqBF7AkGsD+qBBk=; b=oRFcJg08yYC6LtCLXYafD0rk85uuslfCXqFI2MNZZ2pGL2JDQe/B1X8sooD2nCbczI 1LnwDbtLrLJLsPROo+cF2IguZVN+8HRYa8Qpb3IWUiXXnKmzE4UmRkmBi7Pq5TdW6pGZ 2Lvpprxhr89vp6PL86k+5ftQ0WOMxqAxTzxMwBTIox8WTKLx4w29kCI1Kk/g29Nmxc/c Fg5ZNwldDgXKBvEtKPGIc7AfBcJFE2VlMlr0rvsdbom4O2lJtS2g3Ut1zHEVYU6uYROE KlKZE+xx/ClhUbIkyFmLZtWkRX4cX4o9oJHvhRnq9iEBB8OlK0uwFhQKmq9AgiDDPC91 4nmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Lk5vY/CQimKOqdkXmX9OcpY1/cmQPqBF7AkGsD+qBBk=; b=I+V2MJ2c6omzYOSDZqGJue1GrH1FlYFZULUQkdD9YCBbM1LmVvzUksPJNu788HBhC3 bHvNhXEEcZzrvZbbEd6lRP0xX5HPoMrljIkzQdqsBLMBLjKEP2Cjd4DcBOhnkk0QRBSc GcBpma7rALtrl59MlF8E7LLVngvYjwBBm0e2wH3H90roauhIaL8o93mSy/OnVIrYiR9C K/RPZlACuIrG6zF9PTOr64RizQnBQdOx0JOJO/p/7hDXe48CzEFGC90djFrY/WNtaPPz njHTYQ6adbKdUENExON9pJJEJ7+Px6k7cBgY7G1Sw7nIFUi2FLhO2Zt+aSqOOJD8lnEa xfjg== X-Gm-Message-State: APjAAAVCpjpr+hIKOmFnitL7WNhNdqnwFKntPJTJ1U/58+gL0vDUWjlI K3BD/G6/uHX00g5CANIqtiK2Y8LIJg== X-Google-Smtp-Source: APXvYqyCm73K7X3D+iRLKDx/qNKslnaPT3McZN5PU9b2ekkfXfR7GcxVLbUHJSN5HIkw7LCqYVlqts3lrQ== X-Received: by 2002:a1f:ad57:: with SMTP id w84mr10529163vke.63.1572877735384; Mon, 04 Nov 2019 06:28:55 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:38 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-3-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 2/9] kcsan: Add Documentation entry in dev-tools From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Signed-off-by: Marco Elver --- v3: * Split Documentation into separate patch. * Fix typos. * Accuracy: refer to unsoundness/completeness. * Update with new slow-down after optimizations. * Add Alternatives Considered section and move KTSAN mentions there. --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kcsan.rst | 217 ++++++++++++++++++++++++++++++ 2 files changed, 218 insertions(+) create mode 100644 Documentation/dev-tools/kcsan.rst diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index b0522a4dd107..1b756a7014e0 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -21,6 +21,7 @@ whole; patches welcome! kasan ubsan kmemleak + kcsan gdb-kernel-debugging kgdb kselftest diff --git a/Documentation/dev-tools/kcsan.rst b/Documentation/dev-tools/kcsan.rst new file mode 100644 index 000000000000..bf1093b0c64f --- /dev/null +++ b/Documentation/dev-tools/kcsan.rst @@ -0,0 +1,217 @@ +The Kernel Concurrency Sanitizer (KCSAN) +======================================== + +Overview +-------- + +*Kernel Concurrency Sanitizer (KCSAN)* is a dynamic data race detector for +kernel space. KCSAN is a sampling watchpoint-based data race detector. Key +priorities in KCSAN's design are lack of false positives, scalability, and +simplicity. More details can be found in `Implementation Details`_. + +KCSAN uses compile-time instrumentation to instrument memory accesses. KCSAN is +supported in both GCC and Clang. With GCC it requires version 7.3.0 or later. +With Clang it requires version 7.0.0 or later. + +Usage +----- + +To enable KCSAN configure kernel with:: + + CONFIG_KCSAN = y + +KCSAN provides several other configuration options to customize behaviour (see +their respective help text for more info). + +debugfs +~~~~~~~ + +* The file ``/sys/kernel/debug/kcsan`` can be read to get stats. + +* KCSAN can be turned on or off by writing ``on`` or ``off`` to + ``/sys/kernel/debug/kcsan``. + +* Writing ``!some_func_name`` to ``/sys/kernel/debug/kcsan`` adds + ``some_func_name`` to the report filter list, which (by default) blacklists + reporting data races where either one of the top stackframes are a function + in the list. + +* Writing either ``blacklist`` or ``whitelist`` to ``/sys/kernel/debug/kcsan`` + changes the report filtering behaviour. For example, the blacklist feature + can be used to silence frequently occurring data races; the whitelist feature + can help with reproduction and testing of fixes. + +Error reports +~~~~~~~~~~~~~ + +A typical data race report looks like this:: + + ================================================================== + BUG: KCSAN: data-race in generic_permission / kernfs_refresh_inode + + write to 0xffff8fee4c40700c of 4 bytes by task 175 on cpu 4: + kernfs_refresh_inode+0x70/0x170 + kernfs_iop_permission+0x4f/0x90 + inode_permission+0x190/0x200 + link_path_walk.part.0+0x503/0x8e0 + path_lookupat.isra.0+0x69/0x4d0 + filename_lookup+0x136/0x280 + user_path_at_empty+0x47/0x60 + vfs_statx+0x9b/0x130 + __do_sys_newlstat+0x50/0xb0 + __x64_sys_newlstat+0x37/0x50 + do_syscall_64+0x85/0x260 + entry_SYSCALL_64_after_hwframe+0x44/0xa9 + + read to 0xffff8fee4c40700c of 4 bytes by task 166 on cpu 6: + generic_permission+0x5b/0x2a0 + kernfs_iop_permission+0x66/0x90 + inode_permission+0x190/0x200 + link_path_walk.part.0+0x503/0x8e0 + path_lookupat.isra.0+0x69/0x4d0 + filename_lookup+0x136/0x280 + user_path_at_empty+0x47/0x60 + do_faccessat+0x11a/0x390 + __x64_sys_access+0x3c/0x50 + do_syscall_64+0x85/0x260 + entry_SYSCALL_64_after_hwframe+0x44/0xa9 + + Reported by Kernel Concurrency Sanitizer on: + CPU: 6 PID: 166 Comm: systemd-journal Not tainted 5.3.0-rc7+ #1 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 + ================================================================== + +The header of the report provides a short summary of the functions involved in +the race. It is followed by the access types and stack traces of the 2 threads +involved in the data race. + +The other less common type of data race report looks like this:: + + ================================================================== + BUG: KCSAN: data-race in e1000_clean_rx_irq+0x551/0xb10 + + race at unknown origin, with read to 0xffff933db8a2ae6c of 1 bytes by interrupt on cpu 0: + e1000_clean_rx_irq+0x551/0xb10 + e1000_clean+0x533/0xda0 + net_rx_action+0x329/0x900 + __do_softirq+0xdb/0x2db + irq_exit+0x9b/0xa0 + do_IRQ+0x9c/0xf0 + ret_from_intr+0x0/0x18 + default_idle+0x3f/0x220 + arch_cpu_idle+0x21/0x30 + do_idle+0x1df/0x230 + cpu_startup_entry+0x14/0x20 + rest_init+0xc5/0xcb + arch_call_rest_init+0x13/0x2b + start_kernel+0x6db/0x700 + + Reported by Kernel Concurrency Sanitizer on: + CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc7+ #2 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 + ================================================================== + +This report is generated where it was not possible to determine the other +racing thread, but a race was inferred due to the data-value of the watched +memory location having changed. These can occur either due to missing +instrumentation or e.g. DMA accesses. + +Data Races +---------- + +Informally, two operations *conflict* if they access the same memory location, +and at least one of them is a write operation. In an execution, two memory +operations from different threads form a **data race** if they *conflict*, at +least one of them is a *plain access* (non-atomic), and they are *unordered* in +the "happens-before" order according to the `LKMM +<../../tools/memory-model/Documentation/explanation.txt>`_. + +Relationship with the Linux Kernel Memory Model (LKMM) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The LKMM defines the propagation and ordering rules of various memory +operations, which gives developers the ability to reason about concurrent code. +Ultimately this allows to determine the possible executions of concurrent code, +and if that code is free from data races. + +KCSAN is aware of *atomic* accesses (``READ_ONCE``, ``WRITE_ONCE``, +``atomic_*``, etc.), but is oblivious of any ordering guarantees. In other +words, KCSAN assumes that as long as a plain access is not observed to race +with another conflicting access, memory operations are correctly ordered. + +This means that KCSAN will not report *potential* data races due to missing +memory ordering. If, however, missing memory ordering (that is observable with +a particular compiler and architecture) leads to an observable data race (e.g. +entering a critical section erroneously), KCSAN would report the resulting +data race. + +Implementation Details +---------------------- + +The general approach is inspired by `DataCollider +`_. +Unlike DataCollider, KCSAN does not use hardware watchpoints, but instead +relies on compiler instrumentation. Watchpoints are implemented using an +efficient encoding that stores access type, size, and address in a long; the +benefits of using "soft watchpoints" are portability and greater flexibility in +limiting which accesses trigger a watchpoint. + +More specifically, KCSAN requires instrumenting plain (unmarked, non-atomic) +memory operations; for each instrumented plain access: + +1. Check if a matching watchpoint exists; if yes, and at least one access is a + write, then we encountered a racing access. + +2. Periodically, if no matching watchpoint exists, set up a watchpoint and + stall for a small delay. + +3. Also check the data value before the delay, and re-check the data value + after delay; if the values mismatch, we infer a race of unknown origin. + +To detect data races between plain and atomic memory operations, KCSAN also +annotates atomic accesses, but only to check if a watchpoint exists +(``kcsan_check_atomic_*``); i.e. KCSAN never sets up a watchpoint on atomic +accesses. + +Key Properties +~~~~~~~~~~~~~~ + +1. **Memory Overhead:** The current implementation uses a small array of longs + to encode watchpoint information, which is negligible. + +2. **Performance Overhead:** KCSAN's runtime aims to be minimal, using an + efficient watchpoint encoding that does not require acquiring any shared + locks in the fast-path. For kernel boot on a system with 8 CPUs: + + - 5x slow-down with the default KCSAN config; + - 3x slow-down from runtime fast-path overhead only (set very large + ``KCSAN_SKIP_WATCH`` and unset ``KCSAN_SKIP_WATCH_RANDOMIZE``). + +3. **Annotation Overheads:** Minimal annotations are required outside the KCSAN + runtime. As a result, maintenance overheads are minimal as the kernel + evolves. + +4. **Detects Racy Writes from Devices:** Due to checking data values upon + setting up watchpoints, racy writes from devices can also be detected. + +5. **Memory Ordering:** KCSAN is *not* explicitly aware of the LKMM's ordering + rules; this may result in missed data races (false negatives). + +6. **Analysis Accuracy:** For observed executions, due to using a sampling + strategy, the analysis is *unsound* (false negatives possible), but aims to + be complete (no false positives). + +Alternatives Considered +----------------------- + +An alternative data race detection approach for the kernel can be found in +`Kernel Thread Sanitizer (KTSAN) `_. +KTSAN is a happens-before data race detector, which explicitly establishes the +happens-before order between memory operations, which can then be used to +determine data races as defined in `Data Races`_. To build a correct +happens-before relation, KTSAN must be aware of all ordering rules of the LKMM +and synchronization primitives. Unfortunately, any omission leads to false +positives, which is especially important in the context of the kernel which +includes numerous custom synchronization mechanisms. Furthermore, KTSAN's +implementation requires metadata for each memory location (shadow memory); +currently, for each page, KTSAN requires 4 pages of shadow memory. From patchwork Mon Nov 4 14:27:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225917 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AC7591390 for ; Mon, 4 Nov 2019 14:29:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 76BB3217F4 for ; Mon, 4 Nov 2019 14:29:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="HjfM6Wvb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76BB3217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 052EA6B000C; Mon, 4 Nov 2019 09:29:02 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 029956B000E; Mon, 4 Nov 2019 09:29:01 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EAE066B000D; Mon, 4 Nov 2019 09:29:01 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0129.hostedemail.com [216.40.44.129]) by kanga.kvack.org (Postfix) with ESMTP id D2F376B000A for ; Mon, 4 Nov 2019 09:29:01 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 9D66F824999B for ; Mon, 4 Nov 2019 14:29:01 +0000 (UTC) X-FDA: 76118826882.23.fold13_6bd80eca84a0c X-Spam-Summary: 2,0,0,e2aaa42dc49f918a,d41d8cd98f00b204,3qzxaxqukcawqx7q3s00sxq.o0yxuz69-yyw7mow.03s@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:41:152:355:379:541:800:960:973:988:989:1260:1277:1313:1314:1345:1359:1437:1516:1518:1534:1541:1593:1594:1711 :1730:17 X-HE-Tag: fold13_6bd80eca84a0c X-Filterd-Recvd-Size: 4438 Received: from mail-wr1-f74.google.com (mail-wr1-f74.google.com [209.85.221.74]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:00 +0000 (UTC) Received: by mail-wr1-f74.google.com with SMTP id e25so10514363wra.9 for ; Mon, 04 Nov 2019 06:29:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=aW4SA83XYvfgMU7wkWAC5rLE2H9FWpbhI6EjHgaPF1Q=; b=HjfM6Wvb5TrRvQXysjjhAZUXi13FWV60JFteS+oivUITalKiSIDLxLiGVgaE8rjZG2 +dQdZYZI/44MYCotEouoS6TbMnf92clOZmho26Nd1I6Nu5lVM2ZXoM41zy/iZdDffmvE 0SVYiC4IwhQQtpyGFTa+Eu8S4+F3Gfgfxez7s1FWzg825ZLstaiCvlaqstfovKj+O8gX b6K6tBM13jfHVCA8L/MhVc7hwQbXU5lZSIo1Y5mLdyyQ8hbi2YaUotlskJZMMFjch2+1 PEswSISz5h08vomYHGFXbp/Kh9TrObHBabM8gKrGa2nGruMwk7cGij7fbNFqhyQAvADc i+ig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=aW4SA83XYvfgMU7wkWAC5rLE2H9FWpbhI6EjHgaPF1Q=; b=K1H3NCGOwvdu0uMYIjzjnzwdmDu9SiWWtdEpZDksou0PjCUxvzr9+6Z+zq2MH3Mi/J kbWwKjljr7jqHoRZ7xSrZ+ZfaBwZIuwyzpo6wxL5TaaIGTGfYVwJ7pRFjrOWRJPCDZGb itEc2rjvwPPeD37a56EgJIX/walF2ZQy2aRYLYwy2RKiii/P8tCRcLM2MoRk/BswFCtE EB8R6k9Mvbs2eQ+oNB/yt7C1bM92wF+6Bq4Of5D2555vHD90aoLUxeratbgmwUP5/jui 410YyNeNJNCacnEg0r4dOEmY7se7Gnw6Ri6gKaKuFVBc7G6IZbgTCtABAah9wDtSEXEC WROA== X-Gm-Message-State: APjAAAWgavUuk1gC7nLd0rDx1MyixmGsWjsBjvuyfywJ/mFty0mzaknz qRDcPXUPvDgqVPjL/bhtcrgQZ/fU7Q== X-Google-Smtp-Source: APXvYqwpc3TFOOZt+q3MIYWgPWVX1Lm/mb3Jd4l0c4dTAXD7v9VvchXmCDGlKWMT+LJc4C7ZgART+EynnQ== X-Received: by 2002:a05:6000:350:: with SMTP id e16mr25109889wre.276.1572877739417; Mon, 04 Nov 2019 06:28:59 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:39 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-4-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 3/9] objtool, kcsan: Add KCSAN runtime functions to whitelist From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This patch adds KCSAN runtime functions to the objtool whitelist. Signed-off-by: Marco Elver --- v3: * Add missing instrumentation functions. * Use new function names of refactored core runtime. --- tools/objtool/check.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 044c9a3cb247..e022a9a00ca1 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -466,6 +466,24 @@ static const char *uaccess_safe_builtin[] = { "__asan_report_store4_noabort", "__asan_report_store8_noabort", "__asan_report_store16_noabort", + /* KCSAN */ + "kcsan_found_watchpoint", + "kcsan_setup_watchpoint", + /* KCSAN/TSAN */ + "__tsan_func_entry", + "__tsan_func_exit", + "__tsan_read_range", + "__tsan_write_range", + "__tsan_read1", + "__tsan_read2", + "__tsan_read4", + "__tsan_read8", + "__tsan_read16", + "__tsan_write1", + "__tsan_write2", + "__tsan_write4", + "__tsan_write8", + "__tsan_write16", /* KCOV */ "write_comp_data", "__sanitizer_cov_trace_pc", From patchwork Mon Nov 4 14:27:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225923 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B2EAF1390 for ; Mon, 4 Nov 2019 14:29:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 730D3217F4 for ; Mon, 4 Nov 2019 14:29:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="LohiqOAc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 730D3217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A8BDB6B000D; Mon, 4 Nov 2019 09:29:04 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id A150F6B000E; Mon, 4 Nov 2019 09:29:04 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 951886B0010; Mon, 4 Nov 2019 09:29:04 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id 7F7CF6B000D for ; Mon, 4 Nov 2019 09:29:04 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 443CE2839 for ; Mon, 4 Nov 2019 14:29:04 +0000 (UTC) X-FDA: 76118827008.28.bone37_6c390ce2ae92a X-Spam-Summary: 2,0,0,0e864d380de6f847,d41d8cd98f00b204,3rjxaxqukca8t0at6v33v0t.r310x29c-11zaprz.36v@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:41:152:355:379:541:800:960:966:973:988:989:1260:1277:1313:1314:1345:1359:1431:1437:1516:1518:1535:1543:1593: 1594:171 X-HE-Tag: bone37_6c390ce2ae92a X-Filterd-Recvd-Size: 7176 Received: from mail-vk1-f201.google.com (mail-vk1-f201.google.com [209.85.221.201]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:03 +0000 (UTC) Received: by mail-vk1-f201.google.com with SMTP id f73so3104475vka.4 for ; Mon, 04 Nov 2019 06:29:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=pDhjw8llKKibkxwiEHjLwKfV0zoLrBjVR8XQZovar/g=; b=LohiqOAcn6QB64L+xHNmTrNt1oKq4UZRkk4ZOhNrkaIxT1TltVDgpaprtEdibTc9pU A3DldvhOSHYm9RKiNhv/6sRm2D1JbPCRDzgE3/c1GpAU2Jyv8tXRPLu2UNpc6Ukyiz51 SOtLkgj8OZ5YtevqEFEQ6iIBKMWD+3/xzWtyrdxl0scSH5KcQ6ctsCphAu7ip6gQBDL1 Knbbpb+HuMTblcij2UwwdOwlf2vvecyoBV8ZwKls56j6P+XNjjTsTjRq87vdKZE0Xb5r LBfonj+OTaHHrtkacnJyj6KX3UQabQ3eWMCKP9kxDsoEJ4NXEn7JlCddkDBVEI/NHXRh d44Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=pDhjw8llKKibkxwiEHjLwKfV0zoLrBjVR8XQZovar/g=; b=EbSKYSRK+FSqTzvCy9mDISSZMAV4THNikvJYSR1ZQyZ5ke09c05r7ejBXgiZhcoSLI rxz/n847WsKRYMC8SajpdkC8cHLeLXottLfVNHzrDZs5CBIgAyKuiwV3aUIWvnt4AJMe V1nMS2AzgyKkdGyFyH5yZ5VqYt1MdMHxCmw8t2cUqPS8wBJbGKNB11tcblg8L8nkii9f yehPcYX6y2fHMqDCveFxBN00FViXL9RYZSE7Hq5uZLCs/zEGF8/HMa16mC9E7vqjuygv lhXPK/D3oguYloIrMTJZ+8zG8uxALRhh8KK0tXHAftYcZ0f8TtvluFkuJrw70ympFMA3 w3ow== X-Gm-Message-State: APjAAAVF59H1V4dHBpkYB09V/32+EVjFZmWf4ptWW4WT3jfXNmbgu0iH 87JpiEGnoaqCmP/Q7Sr5EE7fWDYiTg== X-Google-Smtp-Source: APXvYqzw3sxkDPv1YzCqpxSha4ijHDPuL+Rfk58iD5OOS4HLDTOu4FfiMAruziYhLL/nRX03UYWRc/epwg== X-Received: by 2002:a67:fd8b:: with SMTP id k11mr11860157vsq.43.1572877742637; Mon, 04 Nov 2019 06:29:02 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:40 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-5-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 4/9] build, kcsan: Add KCSAN build exceptions From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This blacklists several compilation units from KCSAN. See the respective inline comments for the reasoning. Signed-off-by: Marco Elver --- v3: * Moved EFI stub build exception hunk from x86-specific patch, since it's not x86-specific. * Spelling "data-race" -> "data race". --- drivers/firmware/efi/libstub/Makefile | 2 ++ kernel/Makefile | 5 +++++ kernel/sched/Makefile | 6 ++++++ mm/Makefile | 8 ++++++++ 4 files changed, 21 insertions(+) diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index ee0661ddb25b..5d0a645c0de8 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -31,7 +31,9 @@ KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ -D__DISABLE_EXPORTS GCOV_PROFILE := n +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n UBSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y diff --git a/kernel/Makefile b/kernel/Makefile index 74ab46e2ebd1..cc53f7c25446 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -23,6 +23,9 @@ endif # Prevents flicker of uninteresting __do_softirq()/__local_bh_disable_ip() # in coverage traces. KCOV_INSTRUMENT_softirq.o := n +# Avoid KCSAN instrumentation in softirq ("No shared variables, all the data +# are CPU local" => assume no data races), to reduce overhead in interrupts. +KCSAN_SANITIZE_softirq.o = n # These are called from save_stack_trace() on slub debug path, # and produce insane amounts of uninteresting coverage. KCOV_INSTRUMENT_module.o := n @@ -30,6 +33,7 @@ KCOV_INSTRUMENT_extable.o := n # Don't self-instrument. KCOV_INSTRUMENT_kcov.o := n KASAN_SANITIZE_kcov.o := n +KCSAN_SANITIZE_kcov.o := n CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) # cond_syscall is currently not LTO compatible @@ -118,6 +122,7 @@ obj-$(CONFIG_RSEQ) += rseq.o obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o KASAN_SANITIZE_stackleak.o := n +KCSAN_SANITIZE_stackleak.o := n KCOV_INSTRUMENT_stackleak.o := n $(obj)/configs.o: $(obj)/config_data.gz diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 21fb5a5662b5..e9307a9c54e7 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -7,6 +7,12 @@ endif # that is not a function of syscall inputs. E.g. involuntary context switches. KCOV_INSTRUMENT := n +# There are numerous races here, however, most of them due to plain accesses. +# This would make it even harder for syzbot to find reproducers, because these +# bugs trigger without specific input. Disable by default, but should re-enable +# eventually. +KCSAN_SANITIZE := n + ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y) # According to Alan Modra , the -fno-omit-frame-pointer is # needed for x86 only. Why this used to be enabled for all architectures is beyond diff --git a/mm/Makefile b/mm/Makefile index d996846697ef..56c1964bb3a1 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -7,6 +7,14 @@ KASAN_SANITIZE_slab_common.o := n KASAN_SANITIZE_slab.o := n KASAN_SANITIZE_slub.o := n +# These produce frequent data race reports: most of them are due to races on +# the same word but accesses to different bits of that word. Re-enable KCSAN +# for these when we have more consensus on what to do about them. +KCSAN_SANITIZE_slab_common.o := n +KCSAN_SANITIZE_slab.o := n +KCSAN_SANITIZE_slub.o := n +KCSAN_SANITIZE_page_alloc.o := n + # These files are disabled because they produce non-interesting and/or # flaky coverage that is not a function of syscall inputs. E.g. slab is out of # free pages, or a task is migrated between nodes. From patchwork Mon Nov 4 14:27:41 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225925 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BB8861390 for ; Mon, 4 Nov 2019 14:29:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7E2DE217F4 for ; Mon, 4 Nov 2019 14:29:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="XpBlnjzT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E2DE217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D00FB6B0010; Mon, 4 Nov 2019 09:29:07 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id C5DED6B0266; Mon, 4 Nov 2019 09:29:07 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B75106B0269; Mon, 4 Nov 2019 09:29:07 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0063.hostedemail.com [216.40.44.63]) by kanga.kvack.org (Postfix) with ESMTP id 9C16D6B0010 for ; Mon, 4 Nov 2019 09:29:07 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 37D9E441C for ; Mon, 4 Nov 2019 14:29:07 +0000 (UTC) X-FDA: 76118827134.18.rake22_6caf8c4ad2017 X-Spam-Summary: 2,0,0,dbba9eecd6191017,d41d8cd98f00b204,3stxaxqukcbiw3dw9y66y3w.u64305cf-442dsu2.69y@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:2:41:152:355:379:541:800:960:968:973:988:989:1260:1277:1313:1314:1345:1359:1431:1437:1516:1518:1535:1593:159 4:1605:1 X-HE-Tag: rake22_6caf8c4ad2017 X-Filterd-Recvd-Size: 9056 Received: from mail-vs1-f74.google.com (mail-vs1-f74.google.com [209.85.217.74]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:06 +0000 (UTC) Received: by mail-vs1-f74.google.com with SMTP id z20so2797588vsf.1 for ; Mon, 04 Nov 2019 06:29:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=PnlUsFEddsbKHz2GK+uTFYcWeErcIfLobMYOTI3aPFU=; b=XpBlnjzTP/JJfoBTfESYVVCyfq0Y28LdV7cBuhtg6jKBy/OVCuDgML+AEak4DEOggE 4FFwufuSvYhyjQrp6YEdsb+0R9547mXSl11TpqE3J5Gfy2l3SeOKD0jHn1XcAkiVjRsU zFnVpDB/HqpAYH+HlBDp/56aQqgVWbG1whyOoHDFClGVo0d7GgzNehqkJPuug6YEWUX4 GESn0vSshFS4E7Pnv2PBS6OtYbR8LbeNZq2cO3cLxo5KUh9JJuHlMVjnJo2PCOa88WDn E2GYi5/xuLjLSp4mmnif68wguqCwwnHfg6wwkzO66h3CRHGlahAtjZeHjE89Qv4ROYOz wGdg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=PnlUsFEddsbKHz2GK+uTFYcWeErcIfLobMYOTI3aPFU=; b=VFxuR8yRGegLi3xFL04je6AZfPCglHRkavAT7AFU8qUqwdvwsHvtPCaZ802Y2WkPfI pnBh/gcQpTOmWCeK/QhaE5NsY8cOC0GKpOvCJMHAz702g5gK4+kAjh3j+HZ6Zjsvtxru gdJoxKI6DUzAL5Iyl3p2w9/BUc9G2NSFapsddW55mmyauDyfpQjWgcK2plniu18l777R SEh58Y3+mVlxFZogJIgbn4NegdvAZxVemxADHrhpyjo0ET8AiNCRzWjphauap4v7qFLJ qmeN1aRpCC0MZhq0BgpFrEGKifS702sqFmPfOmVRQ1mh0l6gXgG1bAXjbvFpJeUWZunl 3Dzg== X-Gm-Message-State: APjAAAV8CDQC7uvXShK6i+p5G85BVxNEz+ShcGe5pXH3Hn+eWbZ76lHD G1Pw9VdARGgyLVv4CB/rSQAEu5vEUA== X-Google-Smtp-Source: APXvYqyxTcSSDIIgKVC9uqJiIVViZoCP8EgkGFOXLAR6swB3rAeT15fCv8Jgf2+FjQb1O2mN+n5pn+lMvg== X-Received: by 2002:a1f:3249:: with SMTP id y70mr4259895vky.31.1572877745747; Mon, 04 Nov 2019 06:29:05 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:41 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-6-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 5/9] seqlock, kcsan: Add annotations for KCSAN From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Since seqlocks in the Linux kernel do not require the use of marked atomic accesses in critical sections, we teach KCSAN to assume such accesses are atomic. KCSAN currently also pretends that writes to `sequence` are atomic, although currently plain writes are used (their corresponding reads are READ_ONCE). Further, to avoid false positives in the absence of clear ending of a seqlock reader critical section (only when using the raw interface), KCSAN assumes a fixed number of accesses after start of a seqlock critical section are atomic. === Commentary on design around absence of clear begin/end markings === Seqlock usage via seqlock_t follows a predictable usage pattern, where clear critical section begin/end is enforced. With subtle special cases for readers needing to be flat atomic regions, e.g. because usage such as in: - fs/namespace.c:__legitimize_mnt - unbalanced read_seqretry - fs/dcache.c:d_walk - unbalanced need_seqretry But, anything directly accessing seqcount_t seems to be unpredictable. Filtering for usage of read_seqcount_retry not following 'do { .. } while (read_seqcount_retry(..));': $ git grep 'read_seqcount_retry' | grep -Ev 'while \(|seqlock.h|Doc|\* ' => about 1/3 of the total read_seqcount_retry usage. Just looking at fs/namei.c, we conclude that it is non-trivial to prescribe and migrate to an interface that would force clear begin/end seqlock markings for critical sections. As such, we concluded that the best design currently, is to simply ensure that KCSAN works well with the existing code. Signed-off-by: Marco Elver --- v3: * Remove comment from raw_seqcount_barrier that should have been in next patch. * Renamed kcsan_{nestable,flat}_atomic_{begin,end} * Elaborate why clear begin/end cannot be enforced easily. --- include/linux/seqlock.h | 40 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 38 insertions(+), 2 deletions(-) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index bcf4cf26b8c8..61232bc223fd 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -37,8 +37,24 @@ #include #include #include +#include #include +/* + * The seqlock interface does not prescribe a precise sequence of read + * begin/retry/end. For readers, typically there is a call to + * read_seqcount_begin() and read_seqcount_retry(), however, there are more + * esoteric cases which do not follow this pattern. + * + * As a consequence, we take the following best-effort approach for raw usage + * via seqcount_t under KCSAN: upon beginning a seq-reader critical section, + * pessimistically mark then next KCSAN_SEQLOCK_REGION_MAX memory accesses as + * atomics; if there is a matching read_seqcount_retry() call, no following + * memory operations are considered atomic. Usage of seqlocks via seqlock_t + * interface is not affected. + */ +#define KCSAN_SEQLOCK_REGION_MAX 1000 + /* * Version using sequence counter only. * This can be used when code has its own mutex protecting the @@ -115,6 +131,7 @@ static inline unsigned __read_seqcount_begin(const seqcount_t *s) cpu_relax(); goto repeat; } + kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX); return ret; } @@ -131,6 +148,7 @@ static inline unsigned raw_read_seqcount(const seqcount_t *s) { unsigned ret = READ_ONCE(s->sequence); smp_rmb(); + kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX); return ret; } @@ -183,6 +201,7 @@ static inline unsigned raw_seqcount_begin(const seqcount_t *s) { unsigned ret = READ_ONCE(s->sequence); smp_rmb(); + kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX); return ret & ~1; } @@ -202,7 +221,8 @@ static inline unsigned raw_seqcount_begin(const seqcount_t *s) */ static inline int __read_seqcount_retry(const seqcount_t *s, unsigned start) { - return unlikely(s->sequence != start); + kcsan_atomic_next(0); + return unlikely(READ_ONCE(s->sequence) != start); } /** @@ -225,6 +245,7 @@ static inline int read_seqcount_retry(const seqcount_t *s, unsigned start) static inline void raw_write_seqcount_begin(seqcount_t *s) { + kcsan_nestable_atomic_begin(); s->sequence++; smp_wmb(); } @@ -233,6 +254,7 @@ static inline void raw_write_seqcount_end(seqcount_t *s) { smp_wmb(); s->sequence++; + kcsan_nestable_atomic_end(); } /** @@ -271,9 +293,11 @@ static inline void raw_write_seqcount_end(seqcount_t *s) */ static inline void raw_write_seqcount_barrier(seqcount_t *s) { + kcsan_nestable_atomic_begin(); s->sequence++; smp_wmb(); s->sequence++; + kcsan_nestable_atomic_end(); } static inline int raw_read_seqcount_latch(seqcount_t *s) @@ -398,7 +422,9 @@ static inline void write_seqcount_end(seqcount_t *s) static inline void write_seqcount_invalidate(seqcount_t *s) { smp_wmb(); + kcsan_nestable_atomic_begin(); s->sequence+=2; + kcsan_nestable_atomic_end(); } typedef struct { @@ -430,11 +456,21 @@ typedef struct { */ static inline unsigned read_seqbegin(const seqlock_t *sl) { - return read_seqcount_begin(&sl->seqcount); + unsigned ret = read_seqcount_begin(&sl->seqcount); + + kcsan_atomic_next(0); /* non-raw usage, assume closing read_seqretry */ + kcsan_flat_atomic_begin(); + return ret; } static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start) { + /* + * Assume not nested: read_seqretry may be called multiple times when + * completing read critical section. + */ + kcsan_flat_atomic_end(); + return read_seqcount_retry(&sl->seqcount, start); } From patchwork Mon Nov 4 14:27:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225929 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 06A551515 for ; Mon, 4 Nov 2019 14:29:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C7846217F4 for ; Mon, 4 Nov 2019 14:29:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FhPDq8Y8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7846217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 339656B0269; Mon, 4 Nov 2019 09:29:11 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 311556B026A; Mon, 4 Nov 2019 09:29:11 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 13F8E6B026B; Mon, 4 Nov 2019 09:29:11 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0149.hostedemail.com [216.40.44.149]) by kanga.kvack.org (Postfix) with ESMTP id ED5446B0269 for ; Mon, 4 Nov 2019 09:29:10 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id A3F071269 for ; Mon, 4 Nov 2019 14:29:10 +0000 (UTC) X-FDA: 76118827260.05.twist11_6d2981bb27707 X-Spam-Summary: 2,0,0,6923b7ccb362b44c,d41d8cd98f00b204,3ttxaxqukcby07h0d2aa270.ya8749gj-886hwy6.ad2@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:41:152:355:379:541:800:960:967:973:988:989:1260:1277:1313:1314:1345:1359:1437:1516:1518:1535:1542:1593:1594: 1711:173 X-HE-Tag: twist11_6d2981bb27707 X-Filterd-Recvd-Size: 5735 Received: from mail-vs1-f73.google.com (mail-vs1-f73.google.com [209.85.217.73]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:10 +0000 (UTC) Received: by mail-vs1-f73.google.com with SMTP id z19so2790619vso.19 for ; Mon, 04 Nov 2019 06:29:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=sQU0jAVefneuTdQpIgbUF6GdSN4TcMOiQRxRVI16Vls=; b=FhPDq8Y8jgh3GaqH19Ri5l4th6SIgrfB5k6uYp6Qe1zCUALU5Q1h777JkPDXGoqtF+ rUVB4HT5dCMdMd/+svGvi1KkuFsbojwRCgfaJkdh2DPMBB53CrCa1TeF/tRilzh/U2Vv rC8CcHxh3PrEaKH9Qc4nO5dN6oULNuw2D+ebZe/2C78pc5pykjiO0Bg4leEG7yFIFNxI lT1Onq8IrfB98Hhn323WbkEF/3JHPJUZwZzMucC6nWXt4j1r7WLeMRYJuLt6zhN4vW9Q 0cZ7MGwIvE1QsZGodu2uWGo2OqoLsx5v5yIqO4x8fyNCQ7jT/uIEts0ZzNEU0DdB7OYH Ef0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=sQU0jAVefneuTdQpIgbUF6GdSN4TcMOiQRxRVI16Vls=; b=Mqw9CtC/VD8Cgq1S+6ZIOsxEb/Rqmhhx5FEkxOBRd9940dYmDw76adKrLJ5o33URmP Xt+CqGJG9MHYLhH72ZjlsN50aPl88Mqg9dWjXFBBXs9QBxk0H4k/G1Hf+mlrj2Yw7J0m OBRuTttx9zRCGCyU5Iof27yREliE/KVJs/mH1EX9hQueT4e74KbWQbdN8tkYibiVl2d4 xhnI2xQ14T/0QI2v3Wj/l3wnb1bIAemUSPacigbInXjoyNrb73vMNe7yHHVdchvlOudZ Uy+S8yfVFSwhavGzsG4bFKTwK5NPyevz0PsxZu1DV67wfdSp9ikNbo0UrdZJFCpRWihb +pmQ== X-Gm-Message-State: APjAAAUgbEtjy0YuEio5ZBkFZ54PJmSI6OL+ZkA+8R6RvHfgCUg/uGkH GX8mtnhhnEcbILJbAJyvjVp6SyclKQ== X-Google-Smtp-Source: APXvYqxZ17ci8UfBwQliZ986Aa6FaGmsNO4/Ie/63JBd/SxBBgXy0wxlK6hBzj3ifIPGT1Jnqi5jP2CEFw== X-Received: by 2002:a05:6122:2c7:: with SMTP id k7mr10982783vki.97.1572877749135; Mon, 04 Nov 2019 06:29:09 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:42 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-7-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 6/9] seqlock: Require WRITE_ONCE surrounding raw_seqcount_barrier From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This patch proposes to require marked atomic accesses surrounding raw_write_seqcount_barrier. We reason that otherwise there is no way to guarantee propagation nor atomicity of writes before/after the barrier [1]. For example, consider the compiler tears stores either before or after the barrier; in this case, readers may observe a partial value, and because readers are unaware that writes are going on (writes are not in a seq-writer critical section), will complete the seq-reader critical section while having observed some partial state. [1] https://lwn.net/Articles/793253/ This came up when designing and implementing KCSAN, because KCSAN would flag these accesses as data-races. After careful analysis, our reasoning as above led us to conclude that the best thing to do is to propose an amendment to the raw_seqcount_barrier usage. Signed-off-by: Marco Elver --- v3: * Add missing comment that was in preceding seqlock patch. --- include/linux/seqlock.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index 61232bc223fd..f52c91be8939 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -265,6 +265,13 @@ static inline void raw_write_seqcount_end(seqcount_t *s) * usual consistency guarantee. It is one wmb cheaper, because we can * collapse the two back-to-back wmb()s. * + * Note that, writes surrounding the barrier should be declared atomic (e.g. + * via WRITE_ONCE): a) to ensure the writes become visible to other threads + * atomically, avoiding compiler optimizations; b) to document which writes are + * meant to propagate to the reader critical section. This is necessary because + * neither writes before and after the barrier are enclosed in a seq-writer + * critical section that would ensure readers are aware of ongoing writes. + * * seqcount_t seq; * bool X = true, Y = false; * @@ -284,11 +291,11 @@ static inline void raw_write_seqcount_end(seqcount_t *s) * * void write(void) * { - * Y = true; + * WRITE_ONCE(Y, true); * * raw_write_seqcount_barrier(seq); * - * X = false; + * WRITE_ONCE(X, false); * } */ static inline void raw_write_seqcount_barrier(seqcount_t *s) From patchwork Mon Nov 4 14:27:43 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225931 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 698091515 for ; Mon, 4 Nov 2019 14:29:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 284E4217F4 for ; Mon, 4 Nov 2019 14:29:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="U/XYdcDe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 284E4217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BEB0A6B026B; Mon, 4 Nov 2019 09:29:14 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id BC13B6B026C; Mon, 4 Nov 2019 09:29:14 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AFF986B026D; Mon, 4 Nov 2019 09:29:14 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0174.hostedemail.com [216.40.44.174]) by kanga.kvack.org (Postfix) with ESMTP id 9B99C6B026B for ; Mon, 4 Nov 2019 09:29:14 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 604473D09 for ; Mon, 4 Nov 2019 14:29:14 +0000 (UTC) X-FDA: 76118827428.01.brick47_6db3904076259 X-Spam-Summary: 2,0,0,8aee74526b75ea59,d41d8cd98f00b204,3udxaxqukcbk3ak3g5dd5a3.1dba7cjm-bb9kz19.dg5@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:2:41:152:355:379:541:800:960:973:988:989:1260:1277:1313:1314:1345:1359:1437:1516:1518:1535:1593:1594:1605:17 30:1747: X-HE-Tag: brick47_6db3904076259 X-Filterd-Recvd-Size: 9721 Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:13 +0000 (UTC) Received: by mail-wr1-f73.google.com with SMTP id a15so10544791wrr.0 for ; Mon, 04 Nov 2019 06:29:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=dwkrnZGKd1o82vLncnnMx5+hskPdjM10M9XkepioArw=; b=U/XYdcDexJdJytPXnvebCsib+0GCSIPOwwp7Our+Srw04lF1o6qWXtQirdZaNuJDvi PWCZjs8lgfF3WbZz4xb/auZ2JLOMXS22DAbDUAir83/a9im8xzHbMI+3Gu++FTfIcLfu 4N6smqE432wGYXiOL/zZLNF84FWK873RmTrhXDXetMe6YOErFUcq8DANBux5E8sX7L/n ewoK6G/O2gCYatjbKfhV816P7ABJJQjkKZ0IEM6z5SdBMPbKmrPBObno0g9wFbE9TlXT Po2bJCggaH5lttawH0WEhd/kX3X2ZHKDLyD6dRTKJO2pU31u2DoYewsgALhVOX4WYheA iS5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=dwkrnZGKd1o82vLncnnMx5+hskPdjM10M9XkepioArw=; b=V8Kh+kZ/xrnfHE4Urd5G2bs6ZpiEWMcOiAjpirJ9e56hSRWgeIgjAFHooXOGvsPPRC 7dd/O82Qdf1ifuLIb74IHs8G60OnNE0+nk+v/iQ2e4ybj1l1Bv3Jm/Edva/mbW2yzuiM TLB/4Go4kGmabNt+WyyvwJOdX+u88A4PmaJ6Skivi0oKeDmesPX9zZQmq7FsyHAqhLKQ HIzMd6KbGaAoRfxFI4opJwQL3bNOYxgfnYiJb4/aZMLu8gYqGkq7OvHpSS178c+zWvra XxKC9xsn71bdqnkbZakDA+b/bArRUNeOtD64SuxhBzTCNpt+pTb7kvEF2YL0XptheQZ5 4zKw== X-Gm-Message-State: APjAAAW8qo+IucbKnzVJ5zTQbtO2O2qvAna5RJeppPrNgz98kp/emsq/ dWuCf+xoq/xp8QXeqhWfZKrpWXLQSw== X-Google-Smtp-Source: APXvYqwCl8PFLBkBfL5EK6ygI9RFEdP8s5WO4pmDF1xMh0RzOTTNq2VfQ/1s2B6lgxYW8RHEScbPyJRLvw== X-Received: by 2002:a5d:5591:: with SMTP id i17mr22415611wrv.151.1572877752204; Mon, 04 Nov 2019 06:29:12 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:43 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-8-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 7/9] asm-generic, kcsan: Add KCSAN instrumentation for bitops From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Add explicit KCSAN checks for bitops. Signed-off-by: Marco Elver --- v2: * Use kcsan_check{,_atomic}_{read,write} instead of kcsan_check_{access,atomic}. --- include/asm-generic/bitops-instrumented.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/include/asm-generic/bitops-instrumented.h b/include/asm-generic/bitops-instrumented.h index ddd1c6d9d8db..864d707cdb87 100644 --- a/include/asm-generic/bitops-instrumented.h +++ b/include/asm-generic/bitops-instrumented.h @@ -12,6 +12,7 @@ #define _ASM_GENERIC_BITOPS_INSTRUMENTED_H #include +#include /** * set_bit - Atomically set a bit in memory @@ -26,6 +27,7 @@ static inline void set_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); arch_set_bit(nr, addr); } @@ -41,6 +43,7 @@ static inline void set_bit(long nr, volatile unsigned long *addr) static inline void __set_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); arch___set_bit(nr, addr); } @@ -54,6 +57,7 @@ static inline void __set_bit(long nr, volatile unsigned long *addr) static inline void clear_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); arch_clear_bit(nr, addr); } @@ -69,6 +73,7 @@ static inline void clear_bit(long nr, volatile unsigned long *addr) static inline void __clear_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); arch___clear_bit(nr, addr); } @@ -82,6 +87,7 @@ static inline void __clear_bit(long nr, volatile unsigned long *addr) static inline void clear_bit_unlock(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); arch_clear_bit_unlock(nr, addr); } @@ -97,6 +103,7 @@ static inline void clear_bit_unlock(long nr, volatile unsigned long *addr) static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); arch___clear_bit_unlock(nr, addr); } @@ -113,6 +120,7 @@ static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) static inline void change_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); arch_change_bit(nr, addr); } @@ -128,6 +136,7 @@ static inline void change_bit(long nr, volatile unsigned long *addr) static inline void __change_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); arch___change_bit(nr, addr); } @@ -141,6 +150,7 @@ static inline void __change_bit(long nr, volatile unsigned long *addr) static inline bool test_and_set_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); return arch_test_and_set_bit(nr, addr); } @@ -155,6 +165,7 @@ static inline bool test_and_set_bit(long nr, volatile unsigned long *addr) static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); return arch___test_and_set_bit(nr, addr); } @@ -170,6 +181,7 @@ static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr) static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); return arch_test_and_set_bit_lock(nr, addr); } @@ -183,6 +195,7 @@ static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr) static inline bool test_and_clear_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); return arch_test_and_clear_bit(nr, addr); } @@ -197,6 +210,7 @@ static inline bool test_and_clear_bit(long nr, volatile unsigned long *addr) static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); return arch___test_and_clear_bit(nr, addr); } @@ -210,6 +224,7 @@ static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr) static inline bool test_and_change_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); return arch_test_and_change_bit(nr, addr); } @@ -224,6 +239,7 @@ static inline bool test_and_change_bit(long nr, volatile unsigned long *addr) static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_write(addr + BIT_WORD(nr), sizeof(long)); return arch___test_and_change_bit(nr, addr); } @@ -235,6 +251,7 @@ static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr) static inline bool test_bit(long nr, const volatile unsigned long *addr) { kasan_check_read(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_read(addr + BIT_WORD(nr), sizeof(long)); return arch_test_bit(nr, addr); } @@ -254,6 +271,7 @@ static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr) { kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); + kcsan_check_atomic_write(addr + BIT_WORD(nr), sizeof(long)); return arch_clear_bit_unlock_is_negative_byte(nr, addr); } /* Let everybody know we have it. */ From patchwork Mon Nov 4 14:27:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225935 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 10A351599 for ; Mon, 4 Nov 2019 14:29:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8DE372247C for ; Mon, 4 Nov 2019 14:29:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="h7fQiwK5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DE372247C Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C5F156B026D; Mon, 4 Nov 2019 09:29:18 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id C0E496B026E; Mon, 4 Nov 2019 09:29:18 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD75C6B026F; Mon, 4 Nov 2019 09:29:18 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0053.hostedemail.com [216.40.44.53]) by kanga.kvack.org (Postfix) with ESMTP id 8AD606B026D for ; Mon, 4 Nov 2019 09:29:18 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 30937181AEF10 for ; Mon, 4 Nov 2019 14:29:18 +0000 (UTC) X-FDA: 76118827596.05.plate68_6e27b7966f03b X-Spam-Summary: 2,0,0,12715b8f5ff260c6,d41d8cd98f00b204,3uzxaxqukcbw6dn6j8gg8d6.4gedafmp-eecn24c.gj8@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:69:152:355:379:541:960:973:982:988:989:1260:1277:1313:1314:1345:1359:1437:1516:1518:1593:1594:1605:1730:1747 :1777:17 X-HE-Tag: plate68_6e27b7966f03b X-Filterd-Recvd-Size: 63282 Received: from mail-wr1-f74.google.com (mail-wr1-f74.google.com [209.85.221.74]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:16 +0000 (UTC) Received: by mail-wr1-f74.google.com with SMTP id h4so10497417wrx.15 for ; Mon, 04 Nov 2019 06:29:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=b2JEKogI7hW+5Rij0qcxZqdFHMXprK6EtP0aW7w+q08=; b=h7fQiwK52Hpp/O7bdsVhJzQPWMOhQ9XME4dnbFbTrOhVPnKMhDfQ9YWe9StT7jQWYz s7mnM5aH+naYJxhw3Ys1x+sbJJAf1ni9G5twYTKtGF8zDvSelY4N20Eu/OWltaWg9V3y EZfsWIb0Jz4CczN9Rupkv5r5BshTLmeIRfvg+4GULJUyD1ESvnSnS5Wh2Iou0ajbHyue 088ZlthRFU+WbsDmOy6cVoO3JBxDiIiePxpQknHw+K1zRlvcVSb0ozy/C33NED5J/XJP sjvWSs0Xftg6Ms9GHA78K131RTPuNk9Hd0Tc0X/LCn4OmiKE5kp+rTRh03immejuJH2B 8pBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=b2JEKogI7hW+5Rij0qcxZqdFHMXprK6EtP0aW7w+q08=; b=cbBudqJBnI0ejvlT9P33xqUNHTvdJSafM1VRFwN4LXdmlN3opDh4pkUpX5GJL+UecJ ++G4xeveqYs8IRvJvnEffxcDPDvhnm84ywUxGQQW14AAiWbUbjoWyqNwjsWn020wyCp5 ZP1ZLomt1sX4Jjr7PfFeo+aGPEfne1rUlAceiPpsVXPLeNhGw1RrRGuSQiNbJeF0q2Xl xNlNLv+dupjaxDLinbwC5JAF61oJiU2jf3zM0bFJA1VtGGRfSaRe7AbnBGAPYHrca7cf H5gDOqRaayTUTQuWjIteozuZab55pprIYkbAyg8hm+RSKCOEPfmskL+/eszHRNuAxM2d VEqg== X-Gm-Message-State: APjAAAX21zh8Tw9qTgI+3IjaoRf3FnNoeeoEVS8LJZEasCKy+m2UQwko UAKoNnigalBj3b8WK0EZYCgSCWL+3w== X-Google-Smtp-Source: APXvYqwpKVPZaoAlk4LiuvbwJWJeY3EqpVmUxyLfQiWf4SvSQGxEUHthLkXXiUnOzo3BAd/ZK/7xAMIGNg== X-Received: by 2002:adf:dbcd:: with SMTP id e13mr12264676wrj.215.1572877755363; Mon, 04 Nov 2019 06:29:15 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:44 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-9-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 8/9] locking/atomics, kcsan: Add KCSAN instrumentation From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This adds KCSAN instrumentation to atomic-instrumented.h. Signed-off-by: Marco Elver Reviewed-by: Mark Rutland --- v2: * Use kcsan_check{,_atomic}_{read,write} instead of kcsan_check_{access,atomic}. * Introduce __atomic_check_{read,write} [Suggested by Mark Rutland]. --- include/asm-generic/atomic-instrumented.h | 393 +++++++++++----------- scripts/atomic/gen-atomic-instrumented.sh | 17 +- 2 files changed, 218 insertions(+), 192 deletions(-) diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h index e8730c6b9fe2..3dc0f38544f6 100644 --- a/include/asm-generic/atomic-instrumented.h +++ b/include/asm-generic/atomic-instrumented.h @@ -19,11 +19,24 @@ #include #include +#include + +static inline void __atomic_check_read(const volatile void *v, size_t size) +{ + kasan_check_read(v, size); + kcsan_check_atomic_read(v, size); +} + +static inline void __atomic_check_write(const volatile void *v, size_t size) +{ + kasan_check_write(v, size); + kcsan_check_atomic_write(v, size); +} static inline int atomic_read(const atomic_t *v) { - kasan_check_read(v, sizeof(*v)); + __atomic_check_read(v, sizeof(*v)); return arch_atomic_read(v); } #define atomic_read atomic_read @@ -32,7 +45,7 @@ atomic_read(const atomic_t *v) static inline int atomic_read_acquire(const atomic_t *v) { - kasan_check_read(v, sizeof(*v)); + __atomic_check_read(v, sizeof(*v)); return arch_atomic_read_acquire(v); } #define atomic_read_acquire atomic_read_acquire @@ -41,7 +54,7 @@ atomic_read_acquire(const atomic_t *v) static inline void atomic_set(atomic_t *v, int i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_set(v, i); } #define atomic_set atomic_set @@ -50,7 +63,7 @@ atomic_set(atomic_t *v, int i) static inline void atomic_set_release(atomic_t *v, int i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_set_release(v, i); } #define atomic_set_release atomic_set_release @@ -59,7 +72,7 @@ atomic_set_release(atomic_t *v, int i) static inline void atomic_add(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_add(i, v); } #define atomic_add atomic_add @@ -68,7 +81,7 @@ atomic_add(int i, atomic_t *v) static inline int atomic_add_return(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_add_return(i, v); } #define atomic_add_return atomic_add_return @@ -78,7 +91,7 @@ atomic_add_return(int i, atomic_t *v) static inline int atomic_add_return_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_add_return_acquire(i, v); } #define atomic_add_return_acquire atomic_add_return_acquire @@ -88,7 +101,7 @@ atomic_add_return_acquire(int i, atomic_t *v) static inline int atomic_add_return_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_add_return_release(i, v); } #define atomic_add_return_release atomic_add_return_release @@ -98,7 +111,7 @@ atomic_add_return_release(int i, atomic_t *v) static inline int atomic_add_return_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_add_return_relaxed(i, v); } #define atomic_add_return_relaxed atomic_add_return_relaxed @@ -108,7 +121,7 @@ atomic_add_return_relaxed(int i, atomic_t *v) static inline int atomic_fetch_add(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_add(i, v); } #define atomic_fetch_add atomic_fetch_add @@ -118,7 +131,7 @@ atomic_fetch_add(int i, atomic_t *v) static inline int atomic_fetch_add_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_add_acquire(i, v); } #define atomic_fetch_add_acquire atomic_fetch_add_acquire @@ -128,7 +141,7 @@ atomic_fetch_add_acquire(int i, atomic_t *v) static inline int atomic_fetch_add_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_add_release(i, v); } #define atomic_fetch_add_release atomic_fetch_add_release @@ -138,7 +151,7 @@ atomic_fetch_add_release(int i, atomic_t *v) static inline int atomic_fetch_add_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_add_relaxed(i, v); } #define atomic_fetch_add_relaxed atomic_fetch_add_relaxed @@ -147,7 +160,7 @@ atomic_fetch_add_relaxed(int i, atomic_t *v) static inline void atomic_sub(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_sub(i, v); } #define atomic_sub atomic_sub @@ -156,7 +169,7 @@ atomic_sub(int i, atomic_t *v) static inline int atomic_sub_return(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_sub_return(i, v); } #define atomic_sub_return atomic_sub_return @@ -166,7 +179,7 @@ atomic_sub_return(int i, atomic_t *v) static inline int atomic_sub_return_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_sub_return_acquire(i, v); } #define atomic_sub_return_acquire atomic_sub_return_acquire @@ -176,7 +189,7 @@ atomic_sub_return_acquire(int i, atomic_t *v) static inline int atomic_sub_return_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_sub_return_release(i, v); } #define atomic_sub_return_release atomic_sub_return_release @@ -186,7 +199,7 @@ atomic_sub_return_release(int i, atomic_t *v) static inline int atomic_sub_return_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_sub_return_relaxed(i, v); } #define atomic_sub_return_relaxed atomic_sub_return_relaxed @@ -196,7 +209,7 @@ atomic_sub_return_relaxed(int i, atomic_t *v) static inline int atomic_fetch_sub(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_sub(i, v); } #define atomic_fetch_sub atomic_fetch_sub @@ -206,7 +219,7 @@ atomic_fetch_sub(int i, atomic_t *v) static inline int atomic_fetch_sub_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_sub_acquire(i, v); } #define atomic_fetch_sub_acquire atomic_fetch_sub_acquire @@ -216,7 +229,7 @@ atomic_fetch_sub_acquire(int i, atomic_t *v) static inline int atomic_fetch_sub_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_sub_release(i, v); } #define atomic_fetch_sub_release atomic_fetch_sub_release @@ -226,7 +239,7 @@ atomic_fetch_sub_release(int i, atomic_t *v) static inline int atomic_fetch_sub_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_sub_relaxed(i, v); } #define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed @@ -236,7 +249,7 @@ atomic_fetch_sub_relaxed(int i, atomic_t *v) static inline void atomic_inc(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_inc(v); } #define atomic_inc atomic_inc @@ -246,7 +259,7 @@ atomic_inc(atomic_t *v) static inline int atomic_inc_return(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_return(v); } #define atomic_inc_return atomic_inc_return @@ -256,7 +269,7 @@ atomic_inc_return(atomic_t *v) static inline int atomic_inc_return_acquire(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_return_acquire(v); } #define atomic_inc_return_acquire atomic_inc_return_acquire @@ -266,7 +279,7 @@ atomic_inc_return_acquire(atomic_t *v) static inline int atomic_inc_return_release(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_return_release(v); } #define atomic_inc_return_release atomic_inc_return_release @@ -276,7 +289,7 @@ atomic_inc_return_release(atomic_t *v) static inline int atomic_inc_return_relaxed(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_return_relaxed(v); } #define atomic_inc_return_relaxed atomic_inc_return_relaxed @@ -286,7 +299,7 @@ atomic_inc_return_relaxed(atomic_t *v) static inline int atomic_fetch_inc(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_inc(v); } #define atomic_fetch_inc atomic_fetch_inc @@ -296,7 +309,7 @@ atomic_fetch_inc(atomic_t *v) static inline int atomic_fetch_inc_acquire(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_inc_acquire(v); } #define atomic_fetch_inc_acquire atomic_fetch_inc_acquire @@ -306,7 +319,7 @@ atomic_fetch_inc_acquire(atomic_t *v) static inline int atomic_fetch_inc_release(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_inc_release(v); } #define atomic_fetch_inc_release atomic_fetch_inc_release @@ -316,7 +329,7 @@ atomic_fetch_inc_release(atomic_t *v) static inline int atomic_fetch_inc_relaxed(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_inc_relaxed(v); } #define atomic_fetch_inc_relaxed atomic_fetch_inc_relaxed @@ -326,7 +339,7 @@ atomic_fetch_inc_relaxed(atomic_t *v) static inline void atomic_dec(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_dec(v); } #define atomic_dec atomic_dec @@ -336,7 +349,7 @@ atomic_dec(atomic_t *v) static inline int atomic_dec_return(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_return(v); } #define atomic_dec_return atomic_dec_return @@ -346,7 +359,7 @@ atomic_dec_return(atomic_t *v) static inline int atomic_dec_return_acquire(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_return_acquire(v); } #define atomic_dec_return_acquire atomic_dec_return_acquire @@ -356,7 +369,7 @@ atomic_dec_return_acquire(atomic_t *v) static inline int atomic_dec_return_release(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_return_release(v); } #define atomic_dec_return_release atomic_dec_return_release @@ -366,7 +379,7 @@ atomic_dec_return_release(atomic_t *v) static inline int atomic_dec_return_relaxed(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_return_relaxed(v); } #define atomic_dec_return_relaxed atomic_dec_return_relaxed @@ -376,7 +389,7 @@ atomic_dec_return_relaxed(atomic_t *v) static inline int atomic_fetch_dec(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_dec(v); } #define atomic_fetch_dec atomic_fetch_dec @@ -386,7 +399,7 @@ atomic_fetch_dec(atomic_t *v) static inline int atomic_fetch_dec_acquire(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_dec_acquire(v); } #define atomic_fetch_dec_acquire atomic_fetch_dec_acquire @@ -396,7 +409,7 @@ atomic_fetch_dec_acquire(atomic_t *v) static inline int atomic_fetch_dec_release(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_dec_release(v); } #define atomic_fetch_dec_release atomic_fetch_dec_release @@ -406,7 +419,7 @@ atomic_fetch_dec_release(atomic_t *v) static inline int atomic_fetch_dec_relaxed(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_dec_relaxed(v); } #define atomic_fetch_dec_relaxed atomic_fetch_dec_relaxed @@ -415,7 +428,7 @@ atomic_fetch_dec_relaxed(atomic_t *v) static inline void atomic_and(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_and(i, v); } #define atomic_and atomic_and @@ -424,7 +437,7 @@ atomic_and(int i, atomic_t *v) static inline int atomic_fetch_and(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_and(i, v); } #define atomic_fetch_and atomic_fetch_and @@ -434,7 +447,7 @@ atomic_fetch_and(int i, atomic_t *v) static inline int atomic_fetch_and_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_and_acquire(i, v); } #define atomic_fetch_and_acquire atomic_fetch_and_acquire @@ -444,7 +457,7 @@ atomic_fetch_and_acquire(int i, atomic_t *v) static inline int atomic_fetch_and_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_and_release(i, v); } #define atomic_fetch_and_release atomic_fetch_and_release @@ -454,7 +467,7 @@ atomic_fetch_and_release(int i, atomic_t *v) static inline int atomic_fetch_and_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_and_relaxed(i, v); } #define atomic_fetch_and_relaxed atomic_fetch_and_relaxed @@ -464,7 +477,7 @@ atomic_fetch_and_relaxed(int i, atomic_t *v) static inline void atomic_andnot(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_andnot(i, v); } #define atomic_andnot atomic_andnot @@ -474,7 +487,7 @@ atomic_andnot(int i, atomic_t *v) static inline int atomic_fetch_andnot(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_andnot(i, v); } #define atomic_fetch_andnot atomic_fetch_andnot @@ -484,7 +497,7 @@ atomic_fetch_andnot(int i, atomic_t *v) static inline int atomic_fetch_andnot_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_andnot_acquire(i, v); } #define atomic_fetch_andnot_acquire atomic_fetch_andnot_acquire @@ -494,7 +507,7 @@ atomic_fetch_andnot_acquire(int i, atomic_t *v) static inline int atomic_fetch_andnot_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_andnot_release(i, v); } #define atomic_fetch_andnot_release atomic_fetch_andnot_release @@ -504,7 +517,7 @@ atomic_fetch_andnot_release(int i, atomic_t *v) static inline int atomic_fetch_andnot_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_andnot_relaxed(i, v); } #define atomic_fetch_andnot_relaxed atomic_fetch_andnot_relaxed @@ -513,7 +526,7 @@ atomic_fetch_andnot_relaxed(int i, atomic_t *v) static inline void atomic_or(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_or(i, v); } #define atomic_or atomic_or @@ -522,7 +535,7 @@ atomic_or(int i, atomic_t *v) static inline int atomic_fetch_or(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_or(i, v); } #define atomic_fetch_or atomic_fetch_or @@ -532,7 +545,7 @@ atomic_fetch_or(int i, atomic_t *v) static inline int atomic_fetch_or_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_or_acquire(i, v); } #define atomic_fetch_or_acquire atomic_fetch_or_acquire @@ -542,7 +555,7 @@ atomic_fetch_or_acquire(int i, atomic_t *v) static inline int atomic_fetch_or_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_or_release(i, v); } #define atomic_fetch_or_release atomic_fetch_or_release @@ -552,7 +565,7 @@ atomic_fetch_or_release(int i, atomic_t *v) static inline int atomic_fetch_or_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_or_relaxed(i, v); } #define atomic_fetch_or_relaxed atomic_fetch_or_relaxed @@ -561,7 +574,7 @@ atomic_fetch_or_relaxed(int i, atomic_t *v) static inline void atomic_xor(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic_xor(i, v); } #define atomic_xor atomic_xor @@ -570,7 +583,7 @@ atomic_xor(int i, atomic_t *v) static inline int atomic_fetch_xor(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_xor(i, v); } #define atomic_fetch_xor atomic_fetch_xor @@ -580,7 +593,7 @@ atomic_fetch_xor(int i, atomic_t *v) static inline int atomic_fetch_xor_acquire(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_xor_acquire(i, v); } #define atomic_fetch_xor_acquire atomic_fetch_xor_acquire @@ -590,7 +603,7 @@ atomic_fetch_xor_acquire(int i, atomic_t *v) static inline int atomic_fetch_xor_release(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_xor_release(i, v); } #define atomic_fetch_xor_release atomic_fetch_xor_release @@ -600,7 +613,7 @@ atomic_fetch_xor_release(int i, atomic_t *v) static inline int atomic_fetch_xor_relaxed(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_xor_relaxed(i, v); } #define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed @@ -610,7 +623,7 @@ atomic_fetch_xor_relaxed(int i, atomic_t *v) static inline int atomic_xchg(atomic_t *v, int i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_xchg(v, i); } #define atomic_xchg atomic_xchg @@ -620,7 +633,7 @@ atomic_xchg(atomic_t *v, int i) static inline int atomic_xchg_acquire(atomic_t *v, int i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_xchg_acquire(v, i); } #define atomic_xchg_acquire atomic_xchg_acquire @@ -630,7 +643,7 @@ atomic_xchg_acquire(atomic_t *v, int i) static inline int atomic_xchg_release(atomic_t *v, int i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_xchg_release(v, i); } #define atomic_xchg_release atomic_xchg_release @@ -640,7 +653,7 @@ atomic_xchg_release(atomic_t *v, int i) static inline int atomic_xchg_relaxed(atomic_t *v, int i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_xchg_relaxed(v, i); } #define atomic_xchg_relaxed atomic_xchg_relaxed @@ -650,7 +663,7 @@ atomic_xchg_relaxed(atomic_t *v, int i) static inline int atomic_cmpxchg(atomic_t *v, int old, int new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_cmpxchg(v, old, new); } #define atomic_cmpxchg atomic_cmpxchg @@ -660,7 +673,7 @@ atomic_cmpxchg(atomic_t *v, int old, int new) static inline int atomic_cmpxchg_acquire(atomic_t *v, int old, int new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_cmpxchg_acquire(v, old, new); } #define atomic_cmpxchg_acquire atomic_cmpxchg_acquire @@ -670,7 +683,7 @@ atomic_cmpxchg_acquire(atomic_t *v, int old, int new) static inline int atomic_cmpxchg_release(atomic_t *v, int old, int new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_cmpxchg_release(v, old, new); } #define atomic_cmpxchg_release atomic_cmpxchg_release @@ -680,7 +693,7 @@ atomic_cmpxchg_release(atomic_t *v, int old, int new) static inline int atomic_cmpxchg_relaxed(atomic_t *v, int old, int new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_cmpxchg_relaxed(v, old, new); } #define atomic_cmpxchg_relaxed atomic_cmpxchg_relaxed @@ -690,8 +703,8 @@ atomic_cmpxchg_relaxed(atomic_t *v, int old, int new) static inline bool atomic_try_cmpxchg(atomic_t *v, int *old, int new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic_try_cmpxchg(v, old, new); } #define atomic_try_cmpxchg atomic_try_cmpxchg @@ -701,8 +714,8 @@ atomic_try_cmpxchg(atomic_t *v, int *old, int new) static inline bool atomic_try_cmpxchg_acquire(atomic_t *v, int *old, int new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic_try_cmpxchg_acquire(v, old, new); } #define atomic_try_cmpxchg_acquire atomic_try_cmpxchg_acquire @@ -712,8 +725,8 @@ atomic_try_cmpxchg_acquire(atomic_t *v, int *old, int new) static inline bool atomic_try_cmpxchg_release(atomic_t *v, int *old, int new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic_try_cmpxchg_release(v, old, new); } #define atomic_try_cmpxchg_release atomic_try_cmpxchg_release @@ -723,8 +736,8 @@ atomic_try_cmpxchg_release(atomic_t *v, int *old, int new) static inline bool atomic_try_cmpxchg_relaxed(atomic_t *v, int *old, int new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic_try_cmpxchg_relaxed(v, old, new); } #define atomic_try_cmpxchg_relaxed atomic_try_cmpxchg_relaxed @@ -734,7 +747,7 @@ atomic_try_cmpxchg_relaxed(atomic_t *v, int *old, int new) static inline bool atomic_sub_and_test(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_sub_and_test(i, v); } #define atomic_sub_and_test atomic_sub_and_test @@ -744,7 +757,7 @@ atomic_sub_and_test(int i, atomic_t *v) static inline bool atomic_dec_and_test(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_and_test(v); } #define atomic_dec_and_test atomic_dec_and_test @@ -754,7 +767,7 @@ atomic_dec_and_test(atomic_t *v) static inline bool atomic_inc_and_test(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_and_test(v); } #define atomic_inc_and_test atomic_inc_and_test @@ -764,7 +777,7 @@ atomic_inc_and_test(atomic_t *v) static inline bool atomic_add_negative(int i, atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_add_negative(i, v); } #define atomic_add_negative atomic_add_negative @@ -774,7 +787,7 @@ atomic_add_negative(int i, atomic_t *v) static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_fetch_add_unless(v, a, u); } #define atomic_fetch_add_unless atomic_fetch_add_unless @@ -784,7 +797,7 @@ atomic_fetch_add_unless(atomic_t *v, int a, int u) static inline bool atomic_add_unless(atomic_t *v, int a, int u) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_add_unless(v, a, u); } #define atomic_add_unless atomic_add_unless @@ -794,7 +807,7 @@ atomic_add_unless(atomic_t *v, int a, int u) static inline bool atomic_inc_not_zero(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_not_zero(v); } #define atomic_inc_not_zero atomic_inc_not_zero @@ -804,7 +817,7 @@ atomic_inc_not_zero(atomic_t *v) static inline bool atomic_inc_unless_negative(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_inc_unless_negative(v); } #define atomic_inc_unless_negative atomic_inc_unless_negative @@ -814,7 +827,7 @@ atomic_inc_unless_negative(atomic_t *v) static inline bool atomic_dec_unless_positive(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_unless_positive(v); } #define atomic_dec_unless_positive atomic_dec_unless_positive @@ -824,7 +837,7 @@ atomic_dec_unless_positive(atomic_t *v) static inline int atomic_dec_if_positive(atomic_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic_dec_if_positive(v); } #define atomic_dec_if_positive atomic_dec_if_positive @@ -833,7 +846,7 @@ atomic_dec_if_positive(atomic_t *v) static inline s64 atomic64_read(const atomic64_t *v) { - kasan_check_read(v, sizeof(*v)); + __atomic_check_read(v, sizeof(*v)); return arch_atomic64_read(v); } #define atomic64_read atomic64_read @@ -842,7 +855,7 @@ atomic64_read(const atomic64_t *v) static inline s64 atomic64_read_acquire(const atomic64_t *v) { - kasan_check_read(v, sizeof(*v)); + __atomic_check_read(v, sizeof(*v)); return arch_atomic64_read_acquire(v); } #define atomic64_read_acquire atomic64_read_acquire @@ -851,7 +864,7 @@ atomic64_read_acquire(const atomic64_t *v) static inline void atomic64_set(atomic64_t *v, s64 i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_set(v, i); } #define atomic64_set atomic64_set @@ -860,7 +873,7 @@ atomic64_set(atomic64_t *v, s64 i) static inline void atomic64_set_release(atomic64_t *v, s64 i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_set_release(v, i); } #define atomic64_set_release atomic64_set_release @@ -869,7 +882,7 @@ atomic64_set_release(atomic64_t *v, s64 i) static inline void atomic64_add(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_add(i, v); } #define atomic64_add atomic64_add @@ -878,7 +891,7 @@ atomic64_add(s64 i, atomic64_t *v) static inline s64 atomic64_add_return(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_add_return(i, v); } #define atomic64_add_return atomic64_add_return @@ -888,7 +901,7 @@ atomic64_add_return(s64 i, atomic64_t *v) static inline s64 atomic64_add_return_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_add_return_acquire(i, v); } #define atomic64_add_return_acquire atomic64_add_return_acquire @@ -898,7 +911,7 @@ atomic64_add_return_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_add_return_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_add_return_release(i, v); } #define atomic64_add_return_release atomic64_add_return_release @@ -908,7 +921,7 @@ atomic64_add_return_release(s64 i, atomic64_t *v) static inline s64 atomic64_add_return_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_add_return_relaxed(i, v); } #define atomic64_add_return_relaxed atomic64_add_return_relaxed @@ -918,7 +931,7 @@ atomic64_add_return_relaxed(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_add(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_add(i, v); } #define atomic64_fetch_add atomic64_fetch_add @@ -928,7 +941,7 @@ atomic64_fetch_add(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_add_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_add_acquire(i, v); } #define atomic64_fetch_add_acquire atomic64_fetch_add_acquire @@ -938,7 +951,7 @@ atomic64_fetch_add_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_add_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_add_release(i, v); } #define atomic64_fetch_add_release atomic64_fetch_add_release @@ -948,7 +961,7 @@ atomic64_fetch_add_release(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_add_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_add_relaxed(i, v); } #define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed @@ -957,7 +970,7 @@ atomic64_fetch_add_relaxed(s64 i, atomic64_t *v) static inline void atomic64_sub(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_sub(i, v); } #define atomic64_sub atomic64_sub @@ -966,7 +979,7 @@ atomic64_sub(s64 i, atomic64_t *v) static inline s64 atomic64_sub_return(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_sub_return(i, v); } #define atomic64_sub_return atomic64_sub_return @@ -976,7 +989,7 @@ atomic64_sub_return(s64 i, atomic64_t *v) static inline s64 atomic64_sub_return_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_sub_return_acquire(i, v); } #define atomic64_sub_return_acquire atomic64_sub_return_acquire @@ -986,7 +999,7 @@ atomic64_sub_return_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_sub_return_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_sub_return_release(i, v); } #define atomic64_sub_return_release atomic64_sub_return_release @@ -996,7 +1009,7 @@ atomic64_sub_return_release(s64 i, atomic64_t *v) static inline s64 atomic64_sub_return_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_sub_return_relaxed(i, v); } #define atomic64_sub_return_relaxed atomic64_sub_return_relaxed @@ -1006,7 +1019,7 @@ atomic64_sub_return_relaxed(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_sub(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_sub(i, v); } #define atomic64_fetch_sub atomic64_fetch_sub @@ -1016,7 +1029,7 @@ atomic64_fetch_sub(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_sub_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_sub_acquire(i, v); } #define atomic64_fetch_sub_acquire atomic64_fetch_sub_acquire @@ -1026,7 +1039,7 @@ atomic64_fetch_sub_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_sub_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_sub_release(i, v); } #define atomic64_fetch_sub_release atomic64_fetch_sub_release @@ -1036,7 +1049,7 @@ atomic64_fetch_sub_release(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_sub_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_sub_relaxed(i, v); } #define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed @@ -1046,7 +1059,7 @@ atomic64_fetch_sub_relaxed(s64 i, atomic64_t *v) static inline void atomic64_inc(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_inc(v); } #define atomic64_inc atomic64_inc @@ -1056,7 +1069,7 @@ atomic64_inc(atomic64_t *v) static inline s64 atomic64_inc_return(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_return(v); } #define atomic64_inc_return atomic64_inc_return @@ -1066,7 +1079,7 @@ atomic64_inc_return(atomic64_t *v) static inline s64 atomic64_inc_return_acquire(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_return_acquire(v); } #define atomic64_inc_return_acquire atomic64_inc_return_acquire @@ -1076,7 +1089,7 @@ atomic64_inc_return_acquire(atomic64_t *v) static inline s64 atomic64_inc_return_release(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_return_release(v); } #define atomic64_inc_return_release atomic64_inc_return_release @@ -1086,7 +1099,7 @@ atomic64_inc_return_release(atomic64_t *v) static inline s64 atomic64_inc_return_relaxed(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_return_relaxed(v); } #define atomic64_inc_return_relaxed atomic64_inc_return_relaxed @@ -1096,7 +1109,7 @@ atomic64_inc_return_relaxed(atomic64_t *v) static inline s64 atomic64_fetch_inc(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_inc(v); } #define atomic64_fetch_inc atomic64_fetch_inc @@ -1106,7 +1119,7 @@ atomic64_fetch_inc(atomic64_t *v) static inline s64 atomic64_fetch_inc_acquire(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_inc_acquire(v); } #define atomic64_fetch_inc_acquire atomic64_fetch_inc_acquire @@ -1116,7 +1129,7 @@ atomic64_fetch_inc_acquire(atomic64_t *v) static inline s64 atomic64_fetch_inc_release(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_inc_release(v); } #define atomic64_fetch_inc_release atomic64_fetch_inc_release @@ -1126,7 +1139,7 @@ atomic64_fetch_inc_release(atomic64_t *v) static inline s64 atomic64_fetch_inc_relaxed(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_inc_relaxed(v); } #define atomic64_fetch_inc_relaxed atomic64_fetch_inc_relaxed @@ -1136,7 +1149,7 @@ atomic64_fetch_inc_relaxed(atomic64_t *v) static inline void atomic64_dec(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_dec(v); } #define atomic64_dec atomic64_dec @@ -1146,7 +1159,7 @@ atomic64_dec(atomic64_t *v) static inline s64 atomic64_dec_return(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_return(v); } #define atomic64_dec_return atomic64_dec_return @@ -1156,7 +1169,7 @@ atomic64_dec_return(atomic64_t *v) static inline s64 atomic64_dec_return_acquire(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_return_acquire(v); } #define atomic64_dec_return_acquire atomic64_dec_return_acquire @@ -1166,7 +1179,7 @@ atomic64_dec_return_acquire(atomic64_t *v) static inline s64 atomic64_dec_return_release(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_return_release(v); } #define atomic64_dec_return_release atomic64_dec_return_release @@ -1176,7 +1189,7 @@ atomic64_dec_return_release(atomic64_t *v) static inline s64 atomic64_dec_return_relaxed(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_return_relaxed(v); } #define atomic64_dec_return_relaxed atomic64_dec_return_relaxed @@ -1186,7 +1199,7 @@ atomic64_dec_return_relaxed(atomic64_t *v) static inline s64 atomic64_fetch_dec(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_dec(v); } #define atomic64_fetch_dec atomic64_fetch_dec @@ -1196,7 +1209,7 @@ atomic64_fetch_dec(atomic64_t *v) static inline s64 atomic64_fetch_dec_acquire(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_dec_acquire(v); } #define atomic64_fetch_dec_acquire atomic64_fetch_dec_acquire @@ -1206,7 +1219,7 @@ atomic64_fetch_dec_acquire(atomic64_t *v) static inline s64 atomic64_fetch_dec_release(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_dec_release(v); } #define atomic64_fetch_dec_release atomic64_fetch_dec_release @@ -1216,7 +1229,7 @@ atomic64_fetch_dec_release(atomic64_t *v) static inline s64 atomic64_fetch_dec_relaxed(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_dec_relaxed(v); } #define atomic64_fetch_dec_relaxed atomic64_fetch_dec_relaxed @@ -1225,7 +1238,7 @@ atomic64_fetch_dec_relaxed(atomic64_t *v) static inline void atomic64_and(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_and(i, v); } #define atomic64_and atomic64_and @@ -1234,7 +1247,7 @@ atomic64_and(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_and(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_and(i, v); } #define atomic64_fetch_and atomic64_fetch_and @@ -1244,7 +1257,7 @@ atomic64_fetch_and(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_and_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_and_acquire(i, v); } #define atomic64_fetch_and_acquire atomic64_fetch_and_acquire @@ -1254,7 +1267,7 @@ atomic64_fetch_and_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_and_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_and_release(i, v); } #define atomic64_fetch_and_release atomic64_fetch_and_release @@ -1264,7 +1277,7 @@ atomic64_fetch_and_release(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_and_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_and_relaxed(i, v); } #define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed @@ -1274,7 +1287,7 @@ atomic64_fetch_and_relaxed(s64 i, atomic64_t *v) static inline void atomic64_andnot(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_andnot(i, v); } #define atomic64_andnot atomic64_andnot @@ -1284,7 +1297,7 @@ atomic64_andnot(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_andnot(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_andnot(i, v); } #define atomic64_fetch_andnot atomic64_fetch_andnot @@ -1294,7 +1307,7 @@ atomic64_fetch_andnot(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_andnot_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_andnot_acquire(i, v); } #define atomic64_fetch_andnot_acquire atomic64_fetch_andnot_acquire @@ -1304,7 +1317,7 @@ atomic64_fetch_andnot_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_andnot_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_andnot_release(i, v); } #define atomic64_fetch_andnot_release atomic64_fetch_andnot_release @@ -1314,7 +1327,7 @@ atomic64_fetch_andnot_release(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_andnot_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_andnot_relaxed(i, v); } #define atomic64_fetch_andnot_relaxed atomic64_fetch_andnot_relaxed @@ -1323,7 +1336,7 @@ atomic64_fetch_andnot_relaxed(s64 i, atomic64_t *v) static inline void atomic64_or(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_or(i, v); } #define atomic64_or atomic64_or @@ -1332,7 +1345,7 @@ atomic64_or(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_or(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_or(i, v); } #define atomic64_fetch_or atomic64_fetch_or @@ -1342,7 +1355,7 @@ atomic64_fetch_or(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_or_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_or_acquire(i, v); } #define atomic64_fetch_or_acquire atomic64_fetch_or_acquire @@ -1352,7 +1365,7 @@ atomic64_fetch_or_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_or_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_or_release(i, v); } #define atomic64_fetch_or_release atomic64_fetch_or_release @@ -1362,7 +1375,7 @@ atomic64_fetch_or_release(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_or_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_or_relaxed(i, v); } #define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed @@ -1371,7 +1384,7 @@ atomic64_fetch_or_relaxed(s64 i, atomic64_t *v) static inline void atomic64_xor(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); arch_atomic64_xor(i, v); } #define atomic64_xor atomic64_xor @@ -1380,7 +1393,7 @@ atomic64_xor(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_xor(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_xor(i, v); } #define atomic64_fetch_xor atomic64_fetch_xor @@ -1390,7 +1403,7 @@ atomic64_fetch_xor(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_xor_acquire(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_xor_acquire(i, v); } #define atomic64_fetch_xor_acquire atomic64_fetch_xor_acquire @@ -1400,7 +1413,7 @@ atomic64_fetch_xor_acquire(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_xor_release(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_xor_release(i, v); } #define atomic64_fetch_xor_release atomic64_fetch_xor_release @@ -1410,7 +1423,7 @@ atomic64_fetch_xor_release(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_xor_relaxed(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_xor_relaxed(i, v); } #define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed @@ -1420,7 +1433,7 @@ atomic64_fetch_xor_relaxed(s64 i, atomic64_t *v) static inline s64 atomic64_xchg(atomic64_t *v, s64 i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_xchg(v, i); } #define atomic64_xchg atomic64_xchg @@ -1430,7 +1443,7 @@ atomic64_xchg(atomic64_t *v, s64 i) static inline s64 atomic64_xchg_acquire(atomic64_t *v, s64 i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_xchg_acquire(v, i); } #define atomic64_xchg_acquire atomic64_xchg_acquire @@ -1440,7 +1453,7 @@ atomic64_xchg_acquire(atomic64_t *v, s64 i) static inline s64 atomic64_xchg_release(atomic64_t *v, s64 i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_xchg_release(v, i); } #define atomic64_xchg_release atomic64_xchg_release @@ -1450,7 +1463,7 @@ atomic64_xchg_release(atomic64_t *v, s64 i) static inline s64 atomic64_xchg_relaxed(atomic64_t *v, s64 i) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_xchg_relaxed(v, i); } #define atomic64_xchg_relaxed atomic64_xchg_relaxed @@ -1460,7 +1473,7 @@ atomic64_xchg_relaxed(atomic64_t *v, s64 i) static inline s64 atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_cmpxchg(v, old, new); } #define atomic64_cmpxchg atomic64_cmpxchg @@ -1470,7 +1483,7 @@ atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) static inline s64 atomic64_cmpxchg_acquire(atomic64_t *v, s64 old, s64 new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_cmpxchg_acquire(v, old, new); } #define atomic64_cmpxchg_acquire atomic64_cmpxchg_acquire @@ -1480,7 +1493,7 @@ atomic64_cmpxchg_acquire(atomic64_t *v, s64 old, s64 new) static inline s64 atomic64_cmpxchg_release(atomic64_t *v, s64 old, s64 new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_cmpxchg_release(v, old, new); } #define atomic64_cmpxchg_release atomic64_cmpxchg_release @@ -1490,7 +1503,7 @@ atomic64_cmpxchg_release(atomic64_t *v, s64 old, s64 new) static inline s64 atomic64_cmpxchg_relaxed(atomic64_t *v, s64 old, s64 new) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_cmpxchg_relaxed(v, old, new); } #define atomic64_cmpxchg_relaxed atomic64_cmpxchg_relaxed @@ -1500,8 +1513,8 @@ atomic64_cmpxchg_relaxed(atomic64_t *v, s64 old, s64 new) static inline bool atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic64_try_cmpxchg(v, old, new); } #define atomic64_try_cmpxchg atomic64_try_cmpxchg @@ -1511,8 +1524,8 @@ atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) static inline bool atomic64_try_cmpxchg_acquire(atomic64_t *v, s64 *old, s64 new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic64_try_cmpxchg_acquire(v, old, new); } #define atomic64_try_cmpxchg_acquire atomic64_try_cmpxchg_acquire @@ -1522,8 +1535,8 @@ atomic64_try_cmpxchg_acquire(atomic64_t *v, s64 *old, s64 new) static inline bool atomic64_try_cmpxchg_release(atomic64_t *v, s64 *old, s64 new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic64_try_cmpxchg_release(v, old, new); } #define atomic64_try_cmpxchg_release atomic64_try_cmpxchg_release @@ -1533,8 +1546,8 @@ atomic64_try_cmpxchg_release(atomic64_t *v, s64 *old, s64 new) static inline bool atomic64_try_cmpxchg_relaxed(atomic64_t *v, s64 *old, s64 new) { - kasan_check_write(v, sizeof(*v)); - kasan_check_write(old, sizeof(*old)); + __atomic_check_write(v, sizeof(*v)); + __atomic_check_write(old, sizeof(*old)); return arch_atomic64_try_cmpxchg_relaxed(v, old, new); } #define atomic64_try_cmpxchg_relaxed atomic64_try_cmpxchg_relaxed @@ -1544,7 +1557,7 @@ atomic64_try_cmpxchg_relaxed(atomic64_t *v, s64 *old, s64 new) static inline bool atomic64_sub_and_test(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_sub_and_test(i, v); } #define atomic64_sub_and_test atomic64_sub_and_test @@ -1554,7 +1567,7 @@ atomic64_sub_and_test(s64 i, atomic64_t *v) static inline bool atomic64_dec_and_test(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_and_test(v); } #define atomic64_dec_and_test atomic64_dec_and_test @@ -1564,7 +1577,7 @@ atomic64_dec_and_test(atomic64_t *v) static inline bool atomic64_inc_and_test(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_and_test(v); } #define atomic64_inc_and_test atomic64_inc_and_test @@ -1574,7 +1587,7 @@ atomic64_inc_and_test(atomic64_t *v) static inline bool atomic64_add_negative(s64 i, atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_add_negative(i, v); } #define atomic64_add_negative atomic64_add_negative @@ -1584,7 +1597,7 @@ atomic64_add_negative(s64 i, atomic64_t *v) static inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_fetch_add_unless(v, a, u); } #define atomic64_fetch_add_unless atomic64_fetch_add_unless @@ -1594,7 +1607,7 @@ atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) static inline bool atomic64_add_unless(atomic64_t *v, s64 a, s64 u) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_add_unless(v, a, u); } #define atomic64_add_unless atomic64_add_unless @@ -1604,7 +1617,7 @@ atomic64_add_unless(atomic64_t *v, s64 a, s64 u) static inline bool atomic64_inc_not_zero(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_not_zero(v); } #define atomic64_inc_not_zero atomic64_inc_not_zero @@ -1614,7 +1627,7 @@ atomic64_inc_not_zero(atomic64_t *v) static inline bool atomic64_inc_unless_negative(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_inc_unless_negative(v); } #define atomic64_inc_unless_negative atomic64_inc_unless_negative @@ -1624,7 +1637,7 @@ atomic64_inc_unless_negative(atomic64_t *v) static inline bool atomic64_dec_unless_positive(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_unless_positive(v); } #define atomic64_dec_unless_positive atomic64_dec_unless_positive @@ -1634,7 +1647,7 @@ atomic64_dec_unless_positive(atomic64_t *v) static inline s64 atomic64_dec_if_positive(atomic64_t *v) { - kasan_check_write(v, sizeof(*v)); + __atomic_check_write(v, sizeof(*v)); return arch_atomic64_dec_if_positive(v); } #define atomic64_dec_if_positive atomic64_dec_if_positive @@ -1644,7 +1657,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define xchg(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_xchg(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1653,7 +1666,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define xchg_acquire(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_xchg_acquire(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1662,7 +1675,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define xchg_release(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_xchg_release(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1671,7 +1684,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define xchg_relaxed(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_xchg_relaxed(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1680,7 +1693,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1689,7 +1702,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg_acquire(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg_acquire(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1698,7 +1711,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg_release(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg_release(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1707,7 +1720,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg_relaxed(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg_relaxed(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1716,7 +1729,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg64(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg64(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1725,7 +1738,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg64_acquire(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg64_acquire(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1734,7 +1747,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg64_release(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg64_release(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1743,7 +1756,7 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg64_relaxed(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg64_relaxed(__ai_ptr, __VA_ARGS__); \ }) #endif @@ -1751,28 +1764,28 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg_local(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg_local(__ai_ptr, __VA_ARGS__); \ }) #define cmpxchg64_local(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_cmpxchg64_local(__ai_ptr, __VA_ARGS__); \ }) #define sync_cmpxchg(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, sizeof(*__ai_ptr)); \ arch_sync_cmpxchg(__ai_ptr, __VA_ARGS__); \ }) #define cmpxchg_double(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, 2 * sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, 2 * sizeof(*__ai_ptr)); \ arch_cmpxchg_double(__ai_ptr, __VA_ARGS__); \ }) @@ -1780,9 +1793,9 @@ atomic64_dec_if_positive(atomic64_t *v) #define cmpxchg_double_local(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ - kasan_check_write(__ai_ptr, 2 * sizeof(*__ai_ptr)); \ + __atomic_check_write(__ai_ptr, 2 * sizeof(*__ai_ptr)); \ arch_cmpxchg_double_local(__ai_ptr, __VA_ARGS__); \ }) #endif /* _ASM_GENERIC_ATOMIC_INSTRUMENTED_H */ -// b29b625d5de9280f680e42c7be859b55b15e5f6a +// beea41c2a0f2c69e4958ed71bf26f59740fa4b12 diff --git a/scripts/atomic/gen-atomic-instrumented.sh b/scripts/atomic/gen-atomic-instrumented.sh index e09812372b17..8b8b2a6f8d68 100755 --- a/scripts/atomic/gen-atomic-instrumented.sh +++ b/scripts/atomic/gen-atomic-instrumented.sh @@ -20,7 +20,7 @@ gen_param_check() # We don't write to constant parameters [ ${type#c} != ${type} ] && rw="read" - printf "\tkasan_check_${rw}(${name}, sizeof(*${name}));\n" + printf "\t__atomic_check_${rw}(${name}, sizeof(*${name}));\n" } #gen_param_check(arg...) @@ -107,7 +107,7 @@ cat < #include +#include + +static inline void __atomic_check_read(const volatile void *v, size_t size) +{ + kasan_check_read(v, size); + kcsan_check_atomic_read(v, size); +} + +static inline void __atomic_check_write(const volatile void *v, size_t size) +{ + kasan_check_write(v, size); + kcsan_check_atomic_write(v, size); +} EOF From patchwork Mon Nov 4 14:27:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11225939 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7EFA41390 for ; Mon, 4 Nov 2019 14:29:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 31B4A21D7F for ; Mon, 4 Nov 2019 14:29:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RwMp4ufZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31B4A21D7F Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3FA516B026F; Mon, 4 Nov 2019 09:29:21 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 3AC316B0270; Mon, 4 Nov 2019 09:29:21 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C1DF6B0271; Mon, 4 Nov 2019 09:29:21 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0018.hostedemail.com [216.40.44.18]) by kanga.kvack.org (Postfix) with ESMTP id 0EAA66B026F for ; Mon, 4 Nov 2019 09:29:21 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id BBECE181AEF10 for ; Mon, 4 Nov 2019 14:29:20 +0000 (UTC) X-FDA: 76118827680.08.bed69_6e9fd5f0a4a51 X-Spam-Summary: 30,2,0,ded48e2e56931d7b,d41d8cd98f00b204,3vjxaxqukcb89gq9mbjjbg9.7jhgdips-hhfq57f.jmb@flex--elver.bounces.google.com,:elver@google.com:akiyks@gmail.com:stern@rowland.harvard.edu:glider@google.com:parri.andrea@gmail.com:andreyknvl@google.com:luto@kernel.org:ard.biesheuvel@linaro.org:arnd@arndb.de:boqun.feng@gmail.com:bp@alien8.de:dja@axtens.net:dlustig@nvidia.com:dave.hansen@linux.intel.com:dhowells@redhat.com:dvyukov@google.com:hpa@zytor.com:mingo@redhat.com:j.alglave@ucl.ac.uk:joel@joelfernandes.org:corbet@lwn.net:jpoimboe@redhat.com:luc.maranget@inria.fr:mark.rutland@arm.com:npiggin@gmail.com:paulmck@kernel.org:peterz@infradead.org:tglx@linutronix.de:will@kernel.org:kasan-dev@googlegroups.com:linux-arch@vger.kernel.org:linux-doc@vger.kernel.org:linux-efi@vger.kernel.org:linux-kbuild@vger.kernel.org:linux-kernel@vger.kernel.org::x86@kernel.org,RULES_HIT:1:2:41:152:355:379:491:541:800:960:968:973:982:988:989:1260:1277:1313:1314:1345:1359:1437:1516:1518:1593:15 94:1605: X-HE-Tag: bed69_6e9fd5f0a4a51 X-Filterd-Recvd-Size: 10883 Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Nov 2019 14:29:20 +0000 (UTC) Received: by mail-wr1-f73.google.com with SMTP id u2so4381670wrm.7 for ; Mon, 04 Nov 2019 06:29:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=v/fBCawgbNr9z8sHoDyBwn+JenP5278dLuCFcze5nO4=; b=RwMp4ufZMoAcy8AGYLyDxOiK52Y41IM5Omu5uyT1UQikQpowYCEdcb8GrcK71T8g5n C72pggEFwJnmMPerjWv2sTnaV6/S5Yd6Y6O00gERNelbkaBI9N2T1+v4C2nXgYBwo5Rj QaDlbklupShqTrgcnZ2WP6nCfyuM5+zjFaSApzBrMx6qoIMrnUFWntuH2puHKq0HJJhx ofz5Vh2ubSbi72M1x6K6RQiUV4mBMZQYHRvQ7sYWm7ATdo4nulInqcTv+r6ITZ0cQblc IS7EkLHNU3eGauKI/Rostf6g8IXwbewQSkxEDH52jftz5DpxyD+oojQLDNB7m8TR3EAK A/EA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=v/fBCawgbNr9z8sHoDyBwn+JenP5278dLuCFcze5nO4=; b=NR6YAdlV7skSNIh2qrNY6zebt8d7/Um5jCl05ZGG9afnWoKWE+A5OgyUF1jHogqtbR E8Uao6HKfTD4mTE2VeYtugrU2+fwhZqiSi4iN1+Ng/m7TuCE1qSZsluId5Eto5umxwZ3 UtBs/P7FhLzU/IEKv9C/x2mJP8L3JhFekDQNWk0UCBdhwU+7NA2Eyan9oNJlkuArgnJ3 QCb5/KJ4uVZL8pQ3uzTU28aq9MiAibJyF7zvqOHcECTRdrQCVjhVI3dutqYEs6tOqAQg QrveEStX37XM2cv8E6YFsJGllcgEqF8ySWQWWd0Jks1qU83jI6dbLjv+e5Cs6ERkWlap iKDw== X-Gm-Message-State: APjAAAV4qOZ8od3yE+4+85juvZQttmZtgLm7JU3Xk4hdLL+7JB6R7jW4 f1iLjZI0m6ZlMb5n/4mKhj8ytvX1WA== X-Google-Smtp-Source: APXvYqztjJN/esR+L3OUI4QZ+K5dhvl1Dd08UL4fO1/9xBiWuMOU3zCx1yGn64DkSaz9eoQ3fDi32RAqJw== X-Received: by 2002:a5d:4808:: with SMTP id l8mr23085087wrq.118.1572877758478; Mon, 04 Nov 2019 06:29:18 -0800 (PST) Date: Mon, 4 Nov 2019 15:27:45 +0100 In-Reply-To: <20191104142745.14722-1-elver@google.com> Message-Id: <20191104142745.14722-10-elver@google.com> Mime-Version: 1.0 References: <20191104142745.14722-1-elver@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v3 9/9] x86, kcsan: Enable KCSAN for x86 From: Marco Elver To: elver@google.com Cc: akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com, parri.andrea@gmail.com, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, boqun.feng@gmail.com, bp@alien8.de, dja@axtens.net, dlustig@nvidia.com, dave.hansen@linux.intel.com, dhowells@redhat.com, dvyukov@google.com, hpa@zytor.com, mingo@redhat.com, j.alglave@ucl.ac.uk, joel@joelfernandes.org, corbet@lwn.net, jpoimboe@redhat.com, luc.maranget@inria.fr, mark.rutland@arm.com, npiggin@gmail.com, paulmck@kernel.org, peterz@infradead.org, tglx@linutronix.de, will@kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This patch enables KCSAN for x86, with updates to build rules to not use KCSAN for several incompatible compilation units. Signed-off-by: Marco Elver --- v3: * Moved EFI stub build exception hunk to generic build exception patch, since it's not x86-specific. v2: * Document build exceptions where no previous above comment explained why we cannot instrument. --- arch/x86/Kconfig | 1 + arch/x86/boot/Makefile | 2 ++ arch/x86/boot/compressed/Makefile | 2 ++ arch/x86/entry/vdso/Makefile | 3 +++ arch/x86/include/asm/bitops.h | 6 +++++- arch/x86/kernel/Makefile | 7 +++++++ arch/x86/kernel/cpu/Makefile | 3 +++ arch/x86/lib/Makefile | 4 ++++ arch/x86/mm/Makefile | 3 +++ arch/x86/purgatory/Makefile | 2 ++ arch/x86/realmode/Makefile | 3 +++ arch/x86/realmode/rm/Makefile | 3 +++ 12 files changed, 38 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d6e1faa28c58..81859be4a005 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -226,6 +226,7 @@ config X86 select VIRT_TO_BUS select X86_FEATURE_NAMES if PROC_FS select PROC_PID_ARCH_STATUS if PROC_FS + select HAVE_ARCH_KCSAN if X86_64 config INSTRUCTION_DECODER def_bool y diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index e2839b5c246c..9c7942794164 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -9,7 +9,9 @@ # Changed by many, many contributors over the years. # +# Sanitizer runtimes are unavailable and cannot be linked for early boot code. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Kernel does not boot with kcov instrumentation here. diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 6b84afdd7538..a1c248b8439f 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -17,7 +17,9 @@ # (see scripts/Makefile.lib size_append) # compressed vmlinux.bin.all + u32 size of vmlinux.bin.all +# Sanitizer runtimes are unavailable and cannot be linked for early boot code. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 0f2154106d01..a23debaad5b9 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -10,8 +10,11 @@ ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE include $(srctree)/lib/vdso/Makefile KBUILD_CFLAGS += $(DISABLE_LTO) + +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n UBSAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index 7d1f6a49bfae..ee08917d3d92 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -201,8 +201,12 @@ arch_test_and_change_bit(long nr, volatile unsigned long *addr) return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr); } -static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) +static __no_kcsan_or_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) { + /* + * Because this is a plain access, we need to disable KCSAN here to + * avoid double instrumentation via bitops-instrumented.h. + */ return ((1UL << (nr & (BITS_PER_LONG-1))) & (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; } diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 3578ad248bc9..2aa122d94956 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -28,6 +28,13 @@ KASAN_SANITIZE_dumpstack_$(BITS).o := n KASAN_SANITIZE_stacktrace.o := n KASAN_SANITIZE_paravirt.o := n +# Do not instrument early boot code. +KCSAN_SANITIZE_head$(BITS).o := n +# Do not instrument debug code to avoid corrupting bug reporting. +KCSAN_SANITIZE_dumpstack.o := n +KCSAN_SANITIZE_dumpstack_$(BITS).o := n +KCSAN_SANITIZE_stacktrace.o := n + OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y OBJECT_FILES_NON_STANDARD_test_nx.o := y OBJECT_FILES_NON_STANDARD_paravirt_patch.o := y diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index d7a1e5a9331c..1f1b0edc0187 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -13,6 +13,9 @@ endif KCOV_INSTRUMENT_common.o := n KCOV_INSTRUMENT_perf_event.o := n +# As above, instrumenting secondary CPU boot code causes boot hangs. +KCSAN_SANITIZE_common.o := n + # Make sure load_percpu_segment has no stackprotector nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_common.o := $(nostackp) diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 5246db42de45..432a07705677 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -6,10 +6,14 @@ # Produces uninteresting flaky coverage. KCOV_INSTRUMENT_delay.o := n +# KCSAN uses udelay for introducing watchpoint delay; avoid recursion. +KCSAN_SANITIZE_delay.o := n + # Early boot use of cmdline; don't instrument it ifdef CONFIG_AMD_MEM_ENCRYPT KCOV_INSTRUMENT_cmdline.o := n KASAN_SANITIZE_cmdline.o := n +KCSAN_SANITIZE_cmdline.o := n ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_cmdline.o = -pg diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index 84373dc9b341..ee871602f96a 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -7,6 +7,9 @@ KCOV_INSTRUMENT_mem_encrypt_identity.o := n KASAN_SANITIZE_mem_encrypt.o := n KASAN_SANITIZE_mem_encrypt_identity.o := n +KCSAN_SANITIZE_mem_encrypt.o := n +KCSAN_SANITIZE_mem_encrypt_identity.o := n + ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_mem_encrypt.o = -pg CFLAGS_REMOVE_mem_encrypt_identity.o = -pg diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index fb4ee5444379..69379bce9574 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -17,7 +17,9 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib targets += purgatory.ro +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n KCOV_INSTRUMENT := n # These are adjustments to the compiler flags used for objects that diff --git a/arch/x86/realmode/Makefile b/arch/x86/realmode/Makefile index 682c895753d9..6b1f3a4eeb44 100644 --- a/arch/x86/realmode/Makefile +++ b/arch/x86/realmode/Makefile @@ -6,7 +6,10 @@ # for more details. # # + +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y subdir- := rm diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index f60501a384f9..fdbbb945c216 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -6,7 +6,10 @@ # for more details. # # + +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.