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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D267C433EF for ; Wed, 13 Oct 2021 08:51:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86B9561074 for ; Wed, 13 Oct 2021 08:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238927AbhJMIxO (ORCPT ); Wed, 13 Oct 2021 04:53:14 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:42703 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238450AbhJMIxN (ORCPT ); Wed, 13 Oct 2021 04:53:13 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R501e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=31;SR=0;TI=SMTPD_---0UrfYR3s_1634115063; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0UrfYR3s_1634115063) by smtp.aliyun-inc.com(127.0.0.1); Wed, 13 Oct 2021 16:51:04 +0800 To: Guo Ren , Steven Rostedt , Ingo Molnar , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Colin Ian King , Masami Hiramatsu , "Peter Zijlstra (Intel)" , Nicholas Piggin , Jisheng Zhang , linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, live-patching@vger.kernel.org From: =?UTF-8?B?546L6LSH?= Subject: [PATCH v3 0/2] fix & prevent the missing preemption disabling Message-ID: <609b565a-ed6e-a1da-f025-166691b5d994@linux.alibaba.com> Date: Wed, 13 Oct 2021 16:51:03 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The testing show that perf_ftrace_function_call() are using smp_processor_id() with preemption enabled, all the checking on CPU could be wrong after preemption. As Peter point out, the section between ftrace_test_recursion_trylock/unlock() pair require the preemption to be disabled as 'Documentation/trace/ftrace-uses.rst' explained, but currently the work is done outside of the helpers. Patch 1/2 will make sure preemption disabled after trylock() succeed, patch 2/2 will do smp_processor_id() checking after trylock to address the issue. v1: https://lore.kernel.org/all/8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com/ v2: https://lore.kernel.org/all/b1d7fe43-ce84-0ed7-32f7-ea1d12d0b716@linux.alibaba.com/ Michael Wang (2): ftrace: disable preemption between ftrace_test_recursion_trylock/unlock() ftrace: do CPU checking after preemption disabled arch/csky/kernel/probes/ftrace.c | 2 -- arch/parisc/kernel/ftrace.c | 2 -- arch/powerpc/kernel/kprobes-ftrace.c | 2 -- arch/riscv/kernel/probes/ftrace.c | 2 -- arch/x86/kernel/kprobes/ftrace.c | 2 -- include/linux/trace_recursion.h | 17 ++++++++++++++++- kernel/livepatch/patch.c | 13 +++++++------ kernel/trace/trace_event_perf.c | 6 +++--- kernel/trace/trace_functions.c | 5 ----- 9 files changed, 26 insertions(+), 25 deletions(-) -- 1.8.3.1