Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759325AbaDJX1q (ORCPT ); Thu, 10 Apr 2014 19:27:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:6842 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753896AbaDJX1p (ORCPT ); Thu, 10 Apr 2014 19:27:45 -0400 Date: Thu, 10 Apr 2014 19:26:52 -0400 From: Dave Jones To: Jason Low Cc: Peter Zijlstra , "Kirill A. Shutemov" , "Michael L. Semon" , Ingo Molnar , linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com Subject: Re: 3.14.0+/x86: lockdep and mutexes not getting along Message-ID: <20140410232652.GA24658@redhat.com> Mail-Followup-To: Dave Jones , Jason Low , Peter Zijlstra , "Kirill A. Shutemov" , "Michael L. Semon" , Ingo Molnar , linux-kernel@vger.kernel.org, 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1397150084.3032.4.camel@j-VirtualBox> 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 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. 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/