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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 6796FC2B9F4 for ; Mon, 28 Jun 2021 13:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5167B61C80 for ; Mon, 28 Jun 2021 13:50:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232322AbhF1Nwt (ORCPT ); Mon, 28 Jun 2021 09:52:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:54400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232307AbhF1Nwn (ORCPT ); Mon, 28 Jun 2021 09:52:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AB3BD61C74; Mon, 28 Jun 2021 13:50:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624888218; bh=+XEnZXMMZPwmy4U6RRfBJ9DMLt16I883FZaEFdRXwMU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=u5nSUsyZRNVeRBgVGxOsEW2VVhWj0wM+p6hohojLPcL1iPsxy94Vh8MaXU5OUtqoN lqxQF4BOw/iD2pYJuX1STRf8ahlHMdW+l/pyntmRTLldAWYAgplg8AJR4he+zYf65t yJxfazVts9tA+v2NZGcLxoT0TB3Gcl3uLdpU66Bixv+2MVhY98KIthHjdY53jX2jc2 NXtRrHgtgo4GneSJGIuqigTp0Ukn3WSddUZicXk/rZ/fM4U9CEum1G+wO3vurg3hbl 6Le9fJ028Yuy+gUkYDI7XulTTYX50ySi5pe7Rgj4KgP+Z6S1mJIulhM9wJSanZRF/W AtKK75oNsjbEw== Date: Mon, 28 Jun 2021 22:50:13 +0900 From: Masami Hiramatsu To: Masami Hiramatsu Cc: Steven Rostedt , Josh Poimboeuf , Ingo Molnar , X86 ML , 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 , Qiang Wang , Muchun Song Subject: Re: [PATCH -tip v8 00/13] kprobes: Fix stacktrace with kretprobes on x86 Message-Id: <20210628225013.17e14b4c530478e8cc545259@kernel.org> In-Reply-To: <162399992186.506599.8457763707951687195.stgit@devnote2> References: <162399992186.506599.8457763707951687195.stgit@devnote2> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Hi Ingo and Peter, Can you merge this series to tip tree? Josh reviewed the ORC unwinder parts, so I think it is a good time to pick it. (And recently I got same effort from Qiang, he thinks this can be a phishing risk *) * https://lore.kernel.org/bpf/CAMZfGtWPi4CuVOtmUpy2N9J_mvp+5=gSAFvqV1nmvDKP+CAvQA@mail.gmail.com/ Thank you, On Fri, 18 Jun 2021 16:05:22 +0900 Masami Hiramatsu wrote: > Hello, > > Here is the 8th version of the series to fix the stacktrace with kretprobe on x86. > > The previous version is; > > https://lore.kernel.org/bpf/162209754288.436794.3904335049560916855.stgit@devnote2/ > > This version fixes to call appropriate function and drop some unneeded > patches. > > > Changes from v7: > [03/13]: Call dereference_kernel_function_descriptor() for getting the > address of kretprobe_trampoline. > [09/13]: Update the title and description to explain why it is needed. > [10/13][11/13]: Add Josh's Acked-by. > > > > 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, 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-v8 > > > 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: 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/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) -- Masami Hiramatsu