From patchwork Thu Jul 29 14:05:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 12408833 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBF1CC4338F for ; Thu, 29 Jul 2021 14:09:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C53046054E for ; Thu, 29 Jul 2021 14:09:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236996AbhG2OJ0 (ORCPT ); Thu, 29 Jul 2021 10:09:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:55986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237890AbhG2OGu (ORCPT ); Thu, 29 Jul 2021 10:06:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C58AB601FF; Thu, 29 Jul 2021 14:05:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627567560; bh=zdMVzA0jMORbneJQhtqbeyzSAnzLu7XkdM5+ixlxJmQ=; h=From:To:Cc:Subject:Date:From; b=aBJEAXFf+1zEPkfEUu7wU1g0lYW9Z771rFdXiOja7sXxXLmvua/1zDWR6OBAaFEam B0lCLnOdmM7ahS//7qkNsw5NW7sL6+6Rb+d9000fbX/K0g61LjzyKd/nP0PeQFwkq+ OqomxAbM04hhb1CMjEFa0R7PXxapC1n1YQbMNnL1T0qQzHnRRWDVZpXnQ5wgrtIPhF U5LXuLEtTj2AjeVbSXiTV5iy/2g3QEcvFP9nVmUcHR8e/NqK3kpiVDMecZRPj3ShTW juWLVtXMlxYl3kug+wSygM4ohITekI+6zSsABCqY9lkXgxjJAFE84dPZlmxb4Oe5XQ i2jh6+LnitZwg== From: Masami Hiramatsu To: Steven Rostedt , Josh Poimboeuf , Ingo Molnar Cc: X86 ML , Masami Hiramatsu , Daniel Xu , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, Thomas Gleixner , Borislav Petkov , Peter Zijlstra , kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org, Abhishek Sagar , Andrii Nakryiko Subject: [PATCH -tip v10 00/16] kprobes: Fix stacktrace with kretprobes on x86 Date: Thu, 29 Jul 2021 23:05:56 +0900 Message-Id: <162756755600.301564.4957591913842010341.stgit@devnote2> X-Mailer: git-send-email 2.25.1 User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Hello, This is the 10th version of the series to fix the stacktrace with kretprobe on x86. The previous version is here; https://lore.kernel.org/bpf/162601048053.1318837.1550594515476777588.stgit@devnote2/ This version is rebased on top of new kprobes cleanup series(*1) and merging Josh's objtool update series (*2)(*3) as [6/16] and [7/16]. (*1) https://lore.kernel.org/bpf/162748615977.59465.13262421617578791515.stgit@devnote2/ (*2) https://lore.kernel.org/bpf/20210710192433.x5cgjsq2ksvaqnss@treble/ (*3) https://lore.kernel.org/bpf/20210710192514.ghvksi3ozhez4lvb@treble/ Changes from v9: - Add Josh's objtool update patches with a build error fix as [6/16] and [7/16]. - Add a API document for kretprobe_find_ret_addr() and check cur != NULL in [5/16]. With this series, unwinder can unwind stack correctly from ftrace as below; # cd /sys/kernel/debug/tracing # echo > trace # echo 1 > options/sym-offset # echo r vfs_read >> kprobe_events # echo r full_proxy_read >> kprobe_events # echo traceoff:1 > events/kprobes/r_vfs_read_0/trigger # echo stacktrace:1 > events/kprobes/r_full_proxy_read_0/trigger # echo 1 > events/kprobes/enable # cat /sys/kernel/debug/kprobes/list ffffffff8133b740 r full_proxy_read+0x0 [FTRACE] ffffffff812560b0 r vfs_read+0x0 [FTRACE] # echo 0 > events/kprobes/enable # cat trace # tracer: nop # # entries-in-buffer/entries-written: 3/3 #P:8 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <...>-134 [007] ...1 16.185877: r_full_proxy_read_0: (vfs_read+0x98/0x180 <- full_proxy_read) <...>-134 [007] ...1 16.185901: => kretprobe_trace_func+0x209/0x300 => kretprobe_dispatcher+0x4a/0x70 => __kretprobe_trampoline_handler+0xd4/0x170 => trampoline_handler+0x43/0x60 => kretprobe_trampoline+0x2a/0x50 => vfs_read+0x98/0x180 => ksys_read+0x5f/0xe0 => do_syscall_64+0x37/0x90 => entry_SYSCALL_64_after_hwframe+0x44/0xae <...>-134 [007] ...1 16.185902: r_vfs_read_0: (ksys_read+0x5f/0xe0 <- vfs_read) This shows the double return probes (vfs_read() and full_proxy_read()) on the stack correctly unwinded. (vfs_read() returns to 'ksys_read+0x5f' and full_proxy_read() returns to 'vfs_read+0x98') This also changes the kretprobe behavisor a bit, now the instraction pointer in the 'pt_regs' passed to kretprobe user handler is correctly set the real return address. So user handlers can get it via instruction_pointer() API, and can use stack_trace_save_regs(). You can also get this series from git://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git kprobes/kretprobe-stackfix-v9 Thank you, --- Josh Poimboeuf (3): objtool: Add frame-pointer-specific function ignore objtool: Ignore unwind hints for ignored functions x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline() Masami Hiramatsu (13): ia64: kprobes: Fix to pass correct trampoline address to the handler kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor() kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() kprobes: treewide: Make it harder to refer kretprobe_trampoline directly kprobes: Add kretprobe_find_ret_addr() for searching return address ARC: Add instruction_pointer_set() API ia64: Add instruction_pointer_set() API arm: kprobes: Make space for instruction pointer on stack kprobes: Enable stacktrace from pt_regs in kretprobe handler x86/kprobes: Push a fake return address at kretprobe_trampoline x86/unwind: Recover kretprobe trampoline entry tracing: Show kretprobe unknown indicator only for kretprobe_trampoline x86/kprobes: Fixup return address in generic trampoline handler arch/arc/include/asm/kprobes.h | 2 arch/arc/include/asm/ptrace.h | 5 + arch/arc/kernel/kprobes.c | 13 +- arch/arm/probes/kprobes/core.c | 11 +- arch/arm64/include/asm/kprobes.h | 2 arch/arm64/kernel/probes/kprobes.c | 5 - arch/arm64/kernel/probes/kprobes_trampoline.S | 4 - arch/csky/include/asm/kprobes.h | 2 arch/csky/kernel/probes/kprobes.c | 4 - arch/csky/kernel/probes/kprobes_trampoline.S | 4 - arch/ia64/include/asm/ptrace.h | 5 + arch/ia64/kernel/kprobes.c | 15 +-- arch/mips/kernel/kprobes.c | 15 +-- arch/parisc/kernel/kprobes.c | 6 + arch/powerpc/include/asm/kprobes.h | 2 arch/powerpc/kernel/kprobes.c | 29 ++--- arch/powerpc/kernel/optprobes.c | 2 arch/powerpc/kernel/stacktrace.c | 2 arch/riscv/include/asm/kprobes.h | 2 arch/riscv/kernel/probes/kprobes.c | 4 - arch/riscv/kernel/probes/kprobes_trampoline.S | 4 - arch/s390/include/asm/kprobes.h | 2 arch/s390/kernel/kprobes.c | 12 +- arch/s390/kernel/stacktrace.c | 2 arch/sh/include/asm/kprobes.h | 2 arch/sh/kernel/kprobes.c | 12 +- arch/sparc/include/asm/kprobes.h | 2 arch/sparc/kernel/kprobes.c | 12 +- arch/x86/include/asm/kprobes.h | 1 arch/x86/include/asm/unwind.h | 23 ++++ arch/x86/include/asm/unwind_hints.h | 5 + arch/x86/kernel/kprobes/core.c | 71 ++++++++++--- arch/x86/kernel/unwind_frame.c | 3 - arch/x86/kernel/unwind_guess.c | 3 - arch/x86/kernel/unwind_orc.c | 21 +++- include/linux/kprobes.h | 44 +++++++- include/linux/objtool.h | 12 ++ kernel/kprobes.c | 133 +++++++++++++++++++------ kernel/trace/trace_output.c | 17 +-- lib/error-inject.c | 3 - tools/include/linux/objtool.h | 12 ++ tools/objtool/check.c | 2 42 files changed, 360 insertions(+), 172 deletions(-) -- Masami Hiramatsu (Linaro)