From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754150Ab1CYPyB (ORCPT ); Fri, 25 Mar 2011 11:54:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23130 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753984Ab1CYPyA (ORCPT ); Fri, 25 Mar 2011 11:54:00 -0400 Date: Fri, 25 Mar 2011 16:53:56 +0100 From: Jiri Olsa To: Steven Rostedt Cc: Oleg Nesterov , fweisbec@gmail.com, mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCHv3] tracing - avoid soft lockup in trace_pipe Message-ID: <20110325155356.GG1922@jolsa.brq.redhat.com> References: <20110314141853.GB1936@jolsa.brq.redhat.com> <1300112926.9910.100.camel@gandalf.stny.rr.com> <20110314150746.GA4453@jolsa.brq.redhat.com> <1300116057.9910.106.camel@gandalf.stny.rr.com> <20110314180621.GA5987@jolsa.brq.redhat.com> <20110321121008.GA1979@jolsa.brq.redhat.com> <1301019798.14261.159.camel@gandalf.stny.rr.com> <1301022889.14261.167.camel@gandalf.stny.rr.com> <20110325110518.GC1922@jolsa.brq.redhat.com> <1301068177.14261.192.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1301068177.14261.192.camel@gandalf.stny.rr.com> 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 On Fri, Mar 25, 2011 at 11:49:37AM -0400, Steven Rostedt wrote: > On Fri, 2011-03-25 at 12:05 +0100, Jiri Olsa wrote: > > > right, I'm now able to trigger the issue when running setting the tracing > > as said in the patch and plus running this in few instacies: > > > > (while [ 1 ]; do find / > /dev/null ; done) & > > That didn't work for me either. But if I run hackbench 50 on the box, > then the trace does hang while it is running. > > > > > It's strange I did not need this last time.. not sure why :) > > > > > > anyway, the original reproducer I picked this issue from is ltp suite: > > http://sourceforge.net/projects/ltp/files/LTP%20Source/ltp-20100131/ltp-full-20100131.tgz/download > > > > and running following test: > > ltp-full-20101031/testcases/kernel/tracing/ftrace_stress_test/ftrace_stress_test.sh > > > > reproduces the issue all the time for me, and the patch fixies it. > > Attaching patch rebased to the current master with changed comment. > > Thanks, I'll queue it up for 2.6.40, as I do not think this is that > critical of a bug. great, thanks jirka