From patchwork Tue Sep 14 14:38:27 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: 12493669 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=-19.4 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 43C8CC433F5 for ; Tue, 14 Sep 2021 14:38:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21B69610D1 for ; Tue, 14 Sep 2021 14:38:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233585AbhINOjw (ORCPT ); Tue, 14 Sep 2021 10:39:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:60766 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233614AbhINOjt (ORCPT ); Tue, 14 Sep 2021 10:39:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 532B4610A2; Tue, 14 Sep 2021 14:38:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631630311; bh=EpQx0AFCWtfog6vDxcjh3WPnP32jeyKkYz6djXemcis=; h=From:To:Cc:Subject:Date:From; b=HbVaAu2kBM4x4fFhYv1Tkup0Uv6AZZ812iw9eU7KLlGatJGb7xerf1Z5qHBtWUAhF zthQGCi/1H+IeHCKD4gjGrOzl6xIv9yk4+WjkEF/GUppqdy0+rsPBy0dDgLHrPt8f/ j5XXKawvCN12c2QqeEaAHlcDQtQZGqOZjySDDXV7GQO55KMNjgGYZKz79xPwaF71kw iByw1MsxSd3rClzsqswRZs7ArDLwGVKfAB1gw4HcdCrOy+r5lXb4fvbk6F+ing8hYh mNdcZ182w9TDusX5cSKqDZZGpTKWTqOuMf4DrHHa4cuaO1Ymrdeu2NUpgZ20s+GzG3 jsCf8TqKzVO8w== 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 , Paul McKenney Subject: [PATCH -tip v11 00/27] kprobes: Fix stacktrace with kretprobes on x86 Date: Tue, 14 Sep 2021 23:38:27 +0900 Message-Id: <163163030719.489837.2236069935502195491.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 11th version of the series to fix the stacktrace with kretprobe on x86. The previous version is here; https://lore.kernel.org/all/162756755600.301564.4957591913842010341.stgit@devnote2/ This version is rebased on the latest tip/master branch and includes the kprobe cleanup series[1][2]. No code change. [1] https://lore.kernel.org/bpf/162748615977.59465.13262421617578791515.stgit@devnote2/ [2] https://lore.kernel.org/linux-csky/20210727133426.2919710-1-punitagrawal@gmail.com/ 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 ffffffff813bedf0 r full_proxy_read+0x0 [FTRACE] ffffffff812c13e0 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 # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | cat-136 [000] ...1. 14.474966: r_full_proxy_read_0: (vfs_read+0x99/0x190 <- full_proxy_read) cat-136 [000] ...1. 14.474970: => kretprobe_trace_func+0x209/0x300 => kretprobe_dispatcher+0x9d/0xb0 => __kretprobe_trampoline_handler+0xd4/0x1b0 => trampoline_handler+0x43/0x60 => __kretprobe_trampoline+0x2a/0x50 => vfs_read+0x99/0x190 => ksys_read+0x68/0xe0 => do_syscall_64+0x3b/0x90 => entry_SYSCALL_64_after_hwframe+0x44/0xae cat-136 [000] ...1. 14.474971: r_vfs_read_0: (ksys_read+0x68/0xe0 <- 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+0x68' and full_proxy_read() returns to 'vfs_read+0x99') 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-v11 Thank you, Tested-by: Andrii Nakryiko --- 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 (19): kprobes: treewide: Cleanup the error messages for kprobes kprobes: Fix coding style issues kprobes: Use IS_ENABLED() instead of kprobes_built_in() kprobes: Add assertions for required lock kprobes: treewide: Use 'kprobe_opcode_t *' for the code address in get_optimized_kprobe() kprobes: Use bool type for functions which returns boolean value 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 Punit Agrawal (5): kprobes: Do not use local variable when creating debugfs file kprobes: Use helper to parse boolean input from userspace kprobe: Simplify prepare_kprobe() by dropping redundant version csky: ftrace: Drop duplicate implementation of arch_check_ftrace_location() kprobes: Make arch_check_ftrace_location static 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 | 15 - arch/arm/probes/kprobes/opt-arm.c | 7 arch/arm64/include/asm/kprobes.h | 2 arch/arm64/kernel/probes/kprobes.c | 10 arch/arm64/kernel/probes/kprobes_trampoline.S | 4 arch/csky/include/asm/kprobes.h | 2 arch/csky/kernel/probes/ftrace.c | 7 arch/csky/kernel/probes/kprobes.c | 14 - 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 | 26 + arch/parisc/kernel/kprobes.c | 6 arch/powerpc/include/asm/kprobes.h | 2 arch/powerpc/kernel/kprobes.c | 29 - arch/powerpc/kernel/optprobes.c | 8 arch/powerpc/kernel/stacktrace.c | 2 arch/riscv/include/asm/kprobes.h | 2 arch/riscv/kernel/probes/kprobes.c | 15 - arch/riscv/kernel/probes/kprobes_trampoline.S | 4 arch/s390/include/asm/kprobes.h | 2 arch/s390/kernel/kprobes.c | 16 - 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/kprobes/opt.c | 6 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 | 113 ++++-- include/linux/objtool.h | 12 + kernel/kprobes.c | 502 ++++++++++++++----------- kernel/trace/trace_kprobe.c | 2 kernel/trace/trace_output.c | 17 - lib/error-inject.c | 3 tools/include/linux/objtool.h | 12 + tools/objtool/check.c | 2 46 files changed, 607 insertions(+), 436 deletions(-) -- Masami Hiramatsu (Linaro)