From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757546AbYLPVUq (ORCPT ); Tue, 16 Dec 2008 16:20:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751767AbYLPVUi (ORCPT ); Tue, 16 Dec 2008 16:20:38 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:35274 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750730AbYLPVUh (ORCPT ); Tue, 16 Dec 2008 16:20:37 -0500 Date: Tue, 16 Dec 2008 22:20:28 +0100 From: Ingo Molnar To: Frederic Weisbecker Cc: Steven Rostedt , Linux Kernel Subject: Re: [PATCH] tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp() Message-ID: <20081216212028.GP14787@elte.hu> References: <494818EA.7080807@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <494818EA.7080807@gmail.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Frederic Weisbecker wrote: > Impact: prevent a trace recursion > > After some tests with function graph tracer under x86-32, I saw some recursions > caused by ring_buffer_time_stamp() that calls preempt_enable_no_notrace() which > calls preempt_schedule() which is traced itself. > > This patch re-enables preemption without rescheduling. > > Cc: Steven Rostedt > Signed-off-by: Frederic Weisbecker > --- > kernel/trace/ring_buffer.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) applied to tip/tracing/ftrace, thanks Frederic! Does this explain+fix the weird crashes/reboots you were seeing? Ingo