From mboxrd@z Thu Jan 1 00:00:00 1970 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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 712F2C47089 for ; Thu, 27 May 2021 16:41:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E41E61184 for ; Thu, 27 May 2021 16:41:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236559AbhE0QnE (ORCPT ); Thu, 27 May 2021 12:43:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233038AbhE0QnC (ORCPT ); Thu, 27 May 2021 12:43:02 -0400 Received: from mail-yb1-xb2d.google.com (mail-yb1-xb2d.google.com [IPv6:2607:f8b0:4864:20::b2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F18A6C061574; Thu, 27 May 2021 09:41:27 -0700 (PDT) Received: by mail-yb1-xb2d.google.com with SMTP id y2so1499764ybq.13; Thu, 27 May 2021 09:41:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+l4a65SFfahsGPe4r1E9ADTfkqEZTK+KAtWlOZb/3NU=; b=q7xCi4kx6BzY3h/W5ZHyfao57L0zxJqJzX2A/T/IELSwM8dqEY95sW//0R+hzz9Jit SLZuHBQEqvwH6HMtNmb3uNV22TBJJq+e7KkDkgas42uuNU84n8FDocJZhmSjDeBY+O0U bAs71ccpZ7S0nReVn6zNR95pQ2Pdx3qLNb0hHFrAkJHtsiaiYloMBU4YmV9pWSyUHym/ UvjDehY78Fe8JaJkDnz7FplaMZ6JuOlhHD+3OmvJ9TG3FCQQHqdjOKQkY4aTu4qW0LXe 958z4ikn7zJSe2cYWqOe6klqxHJYlwmMVIR4VSJMQlKQPzmCduhQ5QXk6nDIQtUeQfse wU8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=+l4a65SFfahsGPe4r1E9ADTfkqEZTK+KAtWlOZb/3NU=; b=uHo2vx1Mz03/iVjZr0Pf6BSyPgrVeVRMocHEbko6FBoXE1YoTEldkDVbWytcDKfdCH nXtqmhwnUdn/OIImLBrbtwOPVf9ZnSl+tXKQAKaRszD9hFC6oOQ5piej3fr+ZfFZuAs8 bQ/e+YRzBezmEk2uTUM+4I+lnG/PefSULA/ZrPIWjTSmYH1Ip+qC8cz+y1k8f3xHo7TU hPag5OpKjPeyDt9pJG4xx2nMvlLlogSJmH+7WpYHZijoF+uVT22LsWqvTbE4lOpo1XOO HEwqQhE9lU5zlukNkHjudKa8kXyc8Kq9fBNK+W0biYEHPCQotSoJMH0VaC99/DDZhozi sITg== X-Gm-Message-State: AOAM532njzyG4ssYtdh9dJsEqnyL0WmfxkT+UKacu+Q5eMYK5we5IGc3 jKz0Lx7KFt7PAJATUt+pf9uCodQ5svAdjgkw4nc= X-Google-Smtp-Source: ABdhPJw4r3p90tt/mwxh1t6xLrMX5Hq4iefF/RfM7bl+2bAHNjliN/2WZVATvcik5GjUtq1ZgFfSXSBoL/CVyRqZm30= X-Received: by 2002:a25:7246:: with SMTP id n67mr6172067ybc.510.1622133687136; Thu, 27 May 2021 09:41:27 -0700 (PDT) MIME-Version: 1.0 References: <162209754288.436794.3904335049560916855.stgit@devnote2> In-Reply-To: <162209754288.436794.3904335049560916855.stgit@devnote2> From: Andrii Nakryiko Date: Thu, 27 May 2021 09:41:16 -0700 Message-ID: Subject: Re: [PATCH -tip v7 00/13] kprobes: Fix stacktrace with kretprobes on x86 To: Masami Hiramatsu Cc: Steven Rostedt , Ingo Molnar , X86 ML , Daniel Xu , open list , bpf , Jakub Kicinski , Ingo Molnar , Alexei Starovoitov , Thomas Gleixner , Kernel Team , Yonghong Song , Josh Poimboeuf , linux-ia64@vger.kernel.org, Abhishek Sagar Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 26, 2021 at 11:39 PM Masami Hiramatsu wrote: > > Hello, > > Here is the 7th version of the series to fix the stacktrace with kretprobe on x86. > > The previous version is; > > https://lore.kernel.org/bpf/162201612941.278331.5293566981784464165.stgit@devnote2/ > > This version is adding Tested-by from Andrii and do minor cleanups to solve some > warnings from kernel test bots. > > Changes from v6: > For x86 and generic patch: > - Add Andrii's Tested-by. (Andrii, I think you have tested only x86, is it OK?) right, only tested x86-64 > [11/13]: > - Remove superfluous #include . > [13/13]: > - Add a prototype for arch_kretprobe_fixup_return(). > > > 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 will return to ksys_read+0x5f and full_proxy_read > will return to vfs_read+0x98) > > 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-v7 > > > Thank you, > > --- > > Josh Poimboeuf (1): > x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code > > Masami Hiramatsu (12): > 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: 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 > x86/kprobes: Fixup return address in generic trampoline handler > > > 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 | 23 +++++++ > arch/x86/include/asm/unwind_hints.h | 5 ++ > arch/x86/kernel/kprobes/core.c | 53 +++++++++++++++-- > arch/x86/kernel/unwind_frame.c | 3 - > arch/x86/kernel/unwind_guess.c | 3 - > arch/x86/kernel/unwind_orc.c | 18 +++++- > include/linux/kprobes.h | 44 ++++++++++++-- > kernel/kprobes.c | 108 +++++++++++++++++++++++++---------- > kernel/trace/trace_output.c | 17 +----- > lib/error-inject.c | 3 + > 25 files changed, 238 insertions(+), 105 deletions(-) > > -- > Masami Hiramatsu (Linaro)