Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754568AbaDKDsX (ORCPT ); Thu, 10 Apr 2014 23:48:23 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:40049 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753970AbaDKDsW (ORCPT ); Thu, 10 Apr 2014 23:48:22 -0400 Date: Thu, 10 Apr 2014 20:48:16 -0700 From: "Paul E. McKenney" To: Dave Jones , Jason Low , Peter Zijlstra , "Kirill A. Shutemov" , "Michael L. Semon" , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: 3.14.0+/x86: lockdep and mutexes not getting along Message-ID: <20140411034816.GB4496@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20140409121940.GA12890@node.dhcp.inet.fi> <1397108579.2586.15.camel@j-VirtualBox> <20140410091824.GL10526@twins.programming.kicks-ass.net> <1397150084.3032.4.camel@j-VirtualBox> <20140410232652.GA24658@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140410232652.GA24658@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14041103-7164-0000-0000-000000F81751 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 10, 2014 at 07:26:52PM -0400, Dave Jones wrote: > On Thu, Apr 10, 2014 at 10:14:44AM -0700, Jason Low wrote: > > On Thu, 2014-04-10 at 11:18 +0200, Peter Zijlstra wrote: > > > On Wed, Apr 09, 2014 at 10:42:59PM -0700, Jason Low wrote: > > > > As a starting point, would either of you like to test the following > > > > patch to see if it fixes the issue? This patch essentially generates the > > > > same code as in older kernels in the debug case. This applies on top of > > > > kernels with both commits 6f008e72cd11 and 1d8fe7dc8078. > > > > > > > > > So I managed to reproduce, and the below makes it go away. I just don't > > > understand why though. will stare more. > > > > So one thing I noticed that is different in the current code is that in > > debug_mutex_unlock(), there is is a possibility that it does not unlock > > the mutex (when !debug_locks). May be interesting to try out this > > patch too: > > I've been seeing lockups this last week or two too, that manifested by > RCU spewing stall messages, and the box being totally unresponsive. > This patch seems to cure that for me, which I'm sure will make Paul > happy to hear. Whew!!! ;-) Thanx, Paul -- 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/