From patchwork Thu May 27 06:39:03 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: 12283533 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 210ECC4707F for ; Thu, 27 May 2021 06:39:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EEBEE613CC for ; Thu, 27 May 2021 06:39:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229793AbhE0Gkk (ORCPT ); Thu, 27 May 2021 02:40:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:59504 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229603AbhE0Gkj (ORCPT ); Thu, 27 May 2021 02:40:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F0401613C9; Thu, 27 May 2021 06:39:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622097547; bh=XD01Y0bcd5+1m4bw+9rns9YoNtGaOH1c2xAZPCzKXog=; h=From:To:Cc:Subject:Date:From; b=j3aD/gJJjAQ7QtnhBjALtSvw7J5vCOdHLcco/6Sd6aEvlp+L/ZCPGB8DHv2SY8NDy J0oInk6aOmFGfCu5XgMHFOWjF/l6LfZaRI75//px+NWbYP9JZM0RgDpE9mt0gj2Bh3 YW01UFBqO3m+37jpiqcIT/UfDPyumvkGlvCYlUf58DbEcyf3+hQ9MLZcPi4K5143Ws qIuHAq/4C+IFY+U2e8j5lx6s5RQE4+n//CuZ4Z2iZ2NdV+7B77Nr3jSiepe1QoTubt edQBkPwizkDT0cbiv4B3S8bPIv/yXJqoeyX0srjspem8nP3xjkpAGPPDdQeHOjDZxN XAI8V8ea1PI7w== 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 , Andrii Nakryiko Subject: [PATCH -tip v7 00/13] kprobes: Fix stacktrace with kretprobes on x86 Date: Thu, 27 May 2021 15:39:03 +0900 Message-Id: <162209754288.436794.3904335049560916855.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 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?) [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)