From patchwork Fri Jul 12 17:00:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Fernandes X-Patchwork-Id: 11042531 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1767F912 for ; Fri, 12 Jul 2019 17:00:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02033289A5 for ; Fri, 12 Jul 2019 17:00:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E93FB285EC; Fri, 12 Jul 2019 17:00:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 531E628A1B for ; Fri, 12 Jul 2019 17:00:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727428AbfGLRAn (ORCPT ); Fri, 12 Jul 2019 13:00:43 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:38455 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727413AbfGLRAn (ORCPT ); Fri, 12 Jul 2019 13:00:43 -0400 Received: by mail-pf1-f196.google.com with SMTP id y15so4564212pfn.5 for ; Fri, 12 Jul 2019 10:00:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=N6UUFo31dJU7i/TY8ZbCVicJDw2+WbPa1M5E7BmWDCc=; b=QmzQnvFCpnnURvJ3i1kGlgC/mbxaBbaDQHHGSMI654dMso+5TuM3kKX/ZlYDX7gpte MNQrhOSc7NwlgV3l6P5R0r6u2oDqvnlYWxxhmwD1H1ms9D7IAGa9Er0myKsjoYJ+Qxgl 9w0wukZt3X+fvhzBrGOcObP7dPa8ok+/6a9+U= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=N6UUFo31dJU7i/TY8ZbCVicJDw2+WbPa1M5E7BmWDCc=; b=FCN/9CSvoopuajTDZSwDM/x9ZPEClU1joI3upc9jOvuA79SRAUbpGKlp7DtYkRUDPk 2w5TYx5y38reyAGeu0vfu5533toGE0RLI98+ewFYtm40rB9ugM2S1m7eTafc5AhDRdtq UhSxYsoRACt8LyHyPBtHI6mgt0jkBgYP8VgTKGNfOSRFYUg4cpLhu18XObTHFptutHhR Ek240hbO7RIQ4WEqslfgHGE9q/1eHo34Cs6P+6e8mupO9ltVTOfQ+4UjMUyZSVHcfgOT IWnjUUVQpB3+eHUEnKNelOrh4Amp9txdjAp3uaNEGthGhg2yd2HYYtQ27PXq0yvMY1TR c9ow== X-Gm-Message-State: APjAAAWh1MSUAV6OJtOYRUbVnGVARa63ANN24bS6CSW+aTI8PlGGrzU0 iixO76BdR0eK5WYCuvYsp6U= X-Google-Smtp-Source: APXvYqyiiuS0wRYavDuZi49BUv6+XcbUQiNlyObHgTxrpEYMkvdKLXHPO91F4Czqw54uCNVE0428Tg== X-Received: by 2002:a65:6406:: with SMTP id a6mr11576363pgv.393.1562950842022; Fri, 12 Jul 2019 10:00:42 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id a15sm7127385pgw.3.2019.07.12.10.00.37 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 12 Jul 2019 10:00:41 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Alexey Kuznetsov , Bjorn Helgaas , Borislav Petkov , c0d1n61at3@gmail.com, "David S. Miller" , edumazet@google.com, Greg Kroah-Hartman , Hideaki YOSHIFUJI , "H. Peter Anvin" , Ingo Molnar , Jonathan Corbet , Josh Triplett , keescook@chromium.org, kernel-hardening@lists.openwall.com, kernel-team@android.com, Lai Jiangshan , Len Brown , linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Mathieu Desnoyers , neilb@suse.com, netdev@vger.kernel.org, Oleg Nesterov , "Paul E. McKenney" , Pavel Machek , peterz@infradead.org, "Rafael J. Wysocki" , Rasmus Villemoes , rcu@vger.kernel.org, Steven Rostedt , Tejun Heo , Thomas Gleixner , will@kernel.org, x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)) Subject: [PATCH v2 2/9] rcu: Add support for consolidated-RCU reader checking Date: Fri, 12 Jul 2019 13:00:17 -0400 Message-Id: <20190712170024.111093-3-joel@joelfernandes.org> X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog In-Reply-To: <20190712170024.111093-1-joel@joelfernandes.org> References: <20190712170024.111093-1-joel@joelfernandes.org> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch adds support for checking RCU reader sections in list traversal macros. Optionally, if the list macro is called under SRCU or other lock/mutex protection, then appropriate lockdep expressions can be passed to make the checks pass. Existing list_for_each_entry_rcu() invocations don't need to pass the optional fourth argument (cond) unless they are under some non-RCU protection and needs to make lockdep check pass. Signed-off-by: Joel Fernandes (Google) --- include/linux/rculist.h | 28 +++++++++++++++++++++++----- include/linux/rcupdate.h | 7 +++++++ kernel/rcu/Kconfig.debug | 11 +++++++++++ kernel/rcu/update.c | 14 ++++++++++++++ 4 files changed, 55 insertions(+), 5 deletions(-) diff --git a/include/linux/rculist.h b/include/linux/rculist.h index e91ec9ddcd30..1048160625bb 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -40,6 +40,20 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list) */ #define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next))) +/* + * Check during list traversal that we are within an RCU reader + */ + +#ifdef CONFIG_PROVE_RCU_LIST +#define __list_check_rcu(dummy, cond, ...) \ + ({ \ + RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \ + "RCU-list traversed in non-reader section!"); \ + }) +#else +#define __list_check_rcu(dummy, cond, ...) ({}) +#endif + /* * Insert a new entry between two known consecutive entries. * @@ -343,14 +357,16 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_head within the struct. + * @cond: optional lockdep expression if called from non-RCU protection. * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as list_add_rcu() * as long as the traversal is guarded by rcu_read_lock(). */ -#define list_for_each_entry_rcu(pos, head, member) \ - for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \ - &pos->member != (head); \ +#define list_for_each_entry_rcu(pos, head, member, cond...) \ + for (__list_check_rcu(dummy, ## cond, 0), \ + pos = list_entry_rcu((head)->next, typeof(*pos), member); \ + &pos->member != (head); \ pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) /** @@ -616,13 +632,15 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n, * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the hlist_node within the struct. + * @cond: optional lockdep expression if called from non-RCU protection. * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as hlist_add_head_rcu() * as long as the traversal is guarded by rcu_read_lock(). */ -#define hlist_for_each_entry_rcu(pos, head, member) \ - for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ +#define hlist_for_each_entry_rcu(pos, head, member, cond...) \ + for (__list_check_rcu(dummy, ## cond, 0), \ + pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ typeof(*(pos)), member); \ pos; \ pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 922bb6848813..712b464ab960 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -223,6 +223,7 @@ int debug_lockdep_rcu_enabled(void); int rcu_read_lock_held(void); int rcu_read_lock_bh_held(void); int rcu_read_lock_sched_held(void); +int rcu_read_lock_any_held(void); #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ @@ -243,6 +244,12 @@ static inline int rcu_read_lock_sched_held(void) { return !preemptible(); } + +static inline int rcu_read_lock_any_held(void) +{ + return !preemptible(); +} + #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ #ifdef CONFIG_PROVE_RCU diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug index 0ec7d1d33a14..b20d0e2903d1 100644 --- a/kernel/rcu/Kconfig.debug +++ b/kernel/rcu/Kconfig.debug @@ -7,6 +7,17 @@ menu "RCU Debugging" config PROVE_RCU def_bool PROVE_LOCKING +config PROVE_RCU_LIST + bool "RCU list lockdep debugging" + depends on PROVE_RCU + default n + help + Enable RCU lockdep checking for list usages. By default it is + turned off since there are several list RCU users that still + need to be converted to pass a lockdep expression. To prevent + false-positive splats, we keep it default disabled but once all + users are converted, we can remove this config option. + config TORTURE_TEST tristate default n diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index bb961cd89e76..0cc7be0fb6b5 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -294,6 +294,20 @@ int rcu_read_lock_bh_held(void) } EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); +int rcu_read_lock_any_held(void) +{ + if (!debug_lockdep_rcu_enabled()) + return 1; + if (!rcu_is_watching()) + return 0; + if (!rcu_lockdep_current_cpu_online()) + return 0; + if (lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_sched_lock_map)) + return 1; + return !preemptible(); +} +EXPORT_SYMBOL_GPL(rcu_read_lock_any_held); + #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ /**