From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932264Ab1GNTjj (ORCPT ); Thu, 14 Jul 2011 15:39:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49910 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754579Ab1GNTjh (ORCPT ); Thu, 14 Jul 2011 15:39:37 -0400 Date: Thu, 14 Jul 2011 15:38:28 -0400 From: Dave Jones To: "Paul E. McKenney" Cc: Sergey Senozhatsky , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Steven Rostedt , Andrew Morton , Dipankar Sarma , linux-kernel@vger.kernel.org Subject: Re: INFO: possible circular locking dependency detected Message-ID: <20110714193827.GA11552@redhat.com> Mail-Followup-To: Dave Jones , "Paul E. McKenney" , Sergey Senozhatsky , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Steven Rostedt , Andrew Morton , Dipankar Sarma , linux-kernel@vger.kernel.org References: <20110714144946.GA3354@swordfish.minsk.epam.com> <1310661699.2309.13.camel@laptop> <20110714191508.GA3060@swordfish> <20110714193412.GA2317@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110714193412.GA2317@linux.vnet.ibm.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 Thu, Jul 14, 2011 at 12:34:12PM -0700, Paul E. McKenney wrote: > Thank you -- you were indeed running with CONFIG_PREEMPT and > CONFIG_RCU_BOOST, which would be the case for the bug that Steven Rostedt > found. On reproducing, yes, it could be a bit tough, as the race window > is rather narrow. I could probably add delays to force the situation htat > Steven found, but it would be hard to prove that this is your situation. > > Dave, was your lockdep splat also with CONFIG_PREEMPT and > CONFIG_RCU_BOOST? yeah. which might explain why I haven't seen it since. (I usually have it disabled, but turn it on occasionally for a 'lets see what breaks' test) Dave