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 53317C4332F for ; Wed, 13 Oct 2021 03:27:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D1CD60551 for ; Wed, 13 Oct 2021 03:27:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237326AbhJMD3G convert rfc822-to-8bit (ORCPT ); Tue, 12 Oct 2021 23:29:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:59236 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbhJMD3G (ORCPT ); Tue, 12 Oct 2021 23:29:06 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8D494603E8; Wed, 13 Oct 2021 03:27:00 +0000 (UTC) Date: Tue, 12 Oct 2021 23:26:58 -0400 From: Steven Rostedt To: =?UTF-8?B?546L6LSH?= Cc: Guo Ren , 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 Subject: Re: [PATCH v2 0/2] fix & prevent the missing preemption disabling Message-ID: <20211012232658.7dac3f43@oasis.local.home> In-Reply-To: <1a8e8d73-b508-f90b-0d82-eb2da45a720e@linux.alibaba.com> References: <8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com> <1a8e8d73-b508-f90b-0d82-eb2da45a720e@linux.alibaba.com> X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org Please start a new thread when sending new versions. v2 should not be a reply to v1. If you want to reference v1, just add it to the cover letter with a link tag: Link: https://lore.kernel.org/all/8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com/ -- Steve On Wed, 13 Oct 2021 11:16:56 +0800 王贇 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. > > 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. > > 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 | 22 +++++++++++++++++++++- > kernel/livepatch/patch.c | 6 ------ > kernel/trace/trace_event_perf.c | 6 +++--- > kernel/trace/trace_functions.c | 5 ----- > 9 files changed, 24 insertions(+), 25 deletions(-) >