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 48F9DC433F5 for ; Tue, 12 Oct 2021 05:41:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D0346109E for ; Tue, 12 Oct 2021 05:41:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232654AbhJLFnw (ORCPT ); Tue, 12 Oct 2021 01:43:52 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:38229 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229688AbhJLFnv (ORCPT ); Tue, 12 Oct 2021 01:43:51 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R351e4;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_---0UrXyKWV_1634017303; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0UrXyKWV_1634017303) by smtp.aliyun-inc.com(127.0.0.1); Tue, 12 Oct 2021 13:41:45 +0800 Subject: Re: [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing From: =?UTF-8?B?546L6LSH?= 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 References: <8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com> Message-ID: Date: Tue, 12 Oct 2021 13:41:43 +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 In-Reply-To: <8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On 2021/10/12 δΈ‹εˆ1:39, ηŽ‹θ΄‡ wrote: > 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, PATCH 1/2 will fix > that. 2/2 actually. > > Besides, as Peter point out, the testing of recursion within > the section between ftrace_test_recursion_trylock()/_unlock() > pair also need the preemption disabled as the documentation > explained, PATCH 2/2 will make sure on that. 1/2 actually... Regards, Michael Wang > > Michael Wang (2): > ftrace: disable preemption on the testing of recursion > ftrace: prevent preemption in perf_ftrace_function_call() > > 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 | 10 +++++++++- > kernel/livepatch/patch.c | 6 ------ > kernel/trace/trace_event_perf.c | 17 +++++++++++++---- > kernel/trace/trace_functions.c | 5 ----- > 9 files changed, 22 insertions(+), 26 deletions(-) >