Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755271AbYHMHTb (ORCPT ); Wed, 13 Aug 2008 03:19:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752165AbYHMHTU (ORCPT ); Wed, 13 Aug 2008 03:19:20 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:35476 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754748AbYHMHTT (ORCPT ); Wed, 13 Aug 2008 03:19:19 -0400 Date: Wed, 13 Aug 2008 09:19:05 +0200 From: Ingo Molnar To: Bruce Duncan Cc: linux-kernel@vger.kernel.org, Steven Rostedt , Thomas Gleixner , "H. Peter Anvin" Subject: Re: [git pull] ftrace for v2.6.27 Message-ID: <20080813071905.GA18529@elte.hu> References: <20080714142226.GA11412@elte.hu> <200808130248.58216.bwduncan@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200808130248.58216.bwduncan@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 Content-Length: 2195 Lines: 66 * Bruce Duncan wrote: > Hi Ingo, Steven, everyone, > > [ Please CC me in replies ] > > I have just tracked down a regression in 2.6.27-rc2 wrt 2.6.26. Commit > 77a2b37d227483fe52aead242652aee406c25bf0 (ftrace: startup tester on > dynamic tracing.) causes my laptop to fail to resume from S3 (it > simply reboots about a second after the resume starts and the display > never shows anything). > > The patch doesn't revert with patch -R (I don't know if there's a > cleverer way to ask git to revert it), but the problem goes away if I > turn off CONFIG_DYNAMIC_FTRACE. > > The commit and bisect log are attached. Please can you help me to > debug this? could you please send your .config file as well? Suspend+resume bugs are notoriously hard to debug (there's no console output in most cases), so i guess the best way to debug this is for Steve or me to try to reproduce it. Could you send the output of this script: http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh that will tell us what kind of hw you have. and could you perhaps try the patch below? The patch disables on the fly dynamic code patching - which is the primary suspect here. If it makes a difference on your box then a theory would be that ftraced runs too soon after suspend+resume. Ingo -----------------------> Subject: ftrace: debug From: Ingo Molnar Date: Wed Aug 13 09:17:12 CEST 2008 Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux/kernel/trace/ftrace.c =================================================================== --- linux.orig/kernel/trace/ftrace.c +++ linux/kernel/trace/ftrace.c @@ -811,7 +811,7 @@ static int ftraced(void *ignore) /* check once a second */ schedule_timeout(HZ); - if (unlikely(ftrace_disabled)) + if (1) continue; mutex_lock(&ftrace_sysctl_lock); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/