From patchwork Mon Mar 22 06:39:43 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: 12153871 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=-19.2 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 9B85CC433DB for ; Mon, 22 Mar 2021 06:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6600361970 for ; Mon, 22 Mar 2021 06:40:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229840AbhCVGkD (ORCPT ); Mon, 22 Mar 2021 02:40:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:55042 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229548AbhCVGjt (ORCPT ); Mon, 22 Mar 2021 02:39:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 34DDB6195D; Mon, 22 Mar 2021 06:39:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616395189; bh=JxJZI/WgXn+DiTShLLAcZpSNE+5iTUiuX1IRlxYsma0=; h=From:To:Cc:Subject:Date:From; b=sVODjbHxoEJzJnS26eZ8CmJ85cyU5iaU5Qxbd1UkLhXxaCAYE+XqR4Jw5/AhLJlGf kvnM0LohVD5XmQniNdYpchAJHlhTgLNs3uuxTVmdRNG13VbNWSDtWJImGyKP2Rk2jv hkhWbaaJQOPRVNZClq6sHlJ/AgeBpZCEtvmySI5vUKVdHZ9sO3yHImrx1ouZVzO/mC qYgl3OJXv8RsgskvRAcndzC1ftkt6rEIYZFygjKuoUs0yLccquZ1uFGyzRpDOzs1kl 4LS3tYYc5yCZYLt7LzRw14G8EZqTfTaZOY7L0eD4quflyddTcXdRrTwFJQAOc53mME jEQbe0bFC280g== From: Masami Hiramatsu To: Steven Rostedt , 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, tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com, Josh Poimboeuf , linux-ia64@vger.kernel.org, Abhishek Sagar Subject: [PATCH -tip v4 00/12] kprobes: Fix stacktrace with kretprobes on x86 Date: Mon, 22 Mar 2021 15:39:43 +0900 Message-Id: <161639518354.895304.15627519393073806809.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, Here is the 4th version of the series to fix the stacktrace with kretprobe on x86. After merging this, I'll fix other architectures. The previous version is; https://lore.kernel.org/bpf/161615650355.306069.17260992641363840330.stgit@devnote2/ This version fixes some build warnings/errors and a bug on arm. (I think arm's kretprobe implementation is a bit odd. anyway, that is off topic.) [5/12] fixes objtool warning when CONFIG_FRAME_POINTER=y. [7/12] fixes a build error on ia64. And add [8/12] for avoiding stack corruption by instruction_pointer_set() in kretprobe_trampoline_handler on arm. With this series, unwinder can unwind stack correctly from ftrace as below; # cd /sys/kernel/debug/tracing # echo > trace # 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 # echo 1 > options/sym-offset # 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 # | | | |||| | | <...>-135 [005] ...1 9.422114: r_full_proxy_read_0: (vfs_read+0xab/0x1a0 <- full_proxy_read) <...>-135 [005] ...1 9.422158: => kretprobe_trace_func+0x209/0x2f0 => kretprobe_dispatcher+0x4a/0x70 => __kretprobe_trampoline_handler+0xca/0x150 => trampoline_handler+0x44/0x70 => kretprobe_trampoline+0x2a/0x50 => vfs_read+0xab/0x1a0 => ksys_read+0x5f/0xe0 => do_syscall_64+0x33/0x40 => entry_SYSCALL_64_after_hwframe+0x44/0xae => 0 This shows the double return probes (vfs_read and full_proxy_read) on the stack correctly unwinded. (vfs_read was called from ksys_read+0x5f and full_proxy_read was called from vfs_read+0xab) This actually 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. You can also get this series from git://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git kprobes/kretprobe-stackfix-v4 Thank you, --- Josh Poimboeuf (1): x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code Masami Hiramatsu (11): ia64: kprobes: Fix to pass correct trampoline address to the handler kprobes: treewide: Replace arch_deref_entry_point() with dereference_function_descriptor() kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() 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 a space for regs->ARM_pc at kretprobe_trampoline kprobes: Setup instruction pointer in __kretprobe_trampoline_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 arch/arc/include/asm/ptrace.h | 5 ++ arch/arc/kernel/kprobes.c | 2 - arch/arm/probes/kprobes/core.c | 5 +- arch/arm64/kernel/probes/kprobes.c | 3 - arch/csky/kernel/probes/kprobes.c | 2 - arch/ia64/include/asm/ptrace.h | 5 ++ arch/ia64/kernel/kprobes.c | 15 ++--- arch/mips/kernel/kprobes.c | 3 - arch/parisc/kernel/kprobes.c | 4 + arch/powerpc/kernel/kprobes.c | 13 ----- arch/riscv/kernel/probes/kprobes.c | 2 - arch/s390/kernel/kprobes.c | 2 - arch/sh/kernel/kprobes.c | 2 - arch/sparc/kernel/kprobes.c | 2 - arch/x86/include/asm/kprobes.h | 1 arch/x86/include/asm/unwind.h | 17 ++++++ arch/x86/include/asm/unwind_hints.h | 5 ++ arch/x86/kernel/kprobes/core.c | 44 ++++++++++++---- arch/x86/kernel/unwind_frame.c | 4 + arch/x86/kernel/unwind_guess.c | 3 - arch/x86/kernel/unwind_orc.c | 6 +- include/linux/kprobes.h | 41 ++++++++++++-- kernel/kprobes.c | 99 ++++++++++++++++++++++++----------- kernel/trace/trace_output.c | 17 +----- lib/error-inject.c | 3 + 25 files changed, 200 insertions(+), 105 deletions(-) -- Masami Hiramatsu (Linaro)