Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751349Ab3FZFYL (ORCPT ); Wed, 26 Jun 2013 01:24:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40692 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751107Ab3FZFYJ (ORCPT ); Wed, 26 Jun 2013 01:24:09 -0400 Date: Wed, 26 Jun 2013 01:23:52 -0400 From: Dave Jones To: Steven Rostedt Cc: Oleg Nesterov , "Paul E. McKenney" , Linux Kernel , Linus Torvalds , "Eric W. Biederman" , Andrey Vagin Subject: Re: frequent softlockups with 3.10rc6. Message-ID: <20130626052352.GB31416@redhat.com> Mail-Followup-To: Dave Jones , Steven Rostedt , Oleg Nesterov , "Paul E. McKenney" , Linux Kernel , Linus Torvalds , "Eric W. Biederman" , Andrey Vagin References: <20130622013731.GA22918@redhat.com> <20130622173129.GA29375@redhat.com> <20130622215905.GA28238@redhat.com> <20130623143634.GA2000@redhat.com> <20130623150603.GA32313@redhat.com> <20130623160452.GA11740@redhat.com> <20130624155758.GA5993@redhat.com> <20130624173510.GA1321@redhat.com> <20130625153520.GA7784@redhat.com> <1372177414.18733.211.camel@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1372177414.18733.211.camel@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1308 Lines: 36 On Tue, Jun 25, 2013 at 12:23:34PM -0400, Steven Rostedt wrote: > Now, what we can try to do as well, is to add a trigger to disable > tracing, which should (I need to check the code) stop tracing on printk. > To do so: > > # echo printk:traceoff > /sys/kernel/debug/tracing/set_ftrace_filter > > This will add a trigger to the printk function that when called, will > disable tracing. If it is hit before you get your trace, you can just > re-enable tracing with: > > # echo 1 > /sys/kernel/debug/tracing/tracing_on > > Hmm, no it needs a fix to make this work. I applied a patch below that > should do this correctly (and will put this into my 3.11 queue). > > If you run the test again with this change and with the above filter, it > should stop the trace before overwriting the first dump, as it should > ignore the printk output. I think something isn't right with this patch. After 10 hours, I hit the bug again, but... (01:21:28:root@binary:tracing)# cat trace # tracer: preemptirqsoff # (01:21:30:root@binary:tracing)# Dave -- 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/