From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756470Ab3BRI0o (ORCPT ); Mon, 18 Feb 2013 03:26:44 -0500 Received: from mail-ea0-f169.google.com ([209.85.215.169]:57600 "EHLO mail-ea0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752152Ab3BRI0n (ORCPT ); Mon, 18 Feb 2013 03:26:43 -0500 Date: Mon, 18 Feb 2013 09:26:39 +0100 From: Ingo Molnar To: Sasha Levin Cc: Ingo Molnar , Thomas Gleixner , Peter Zijlstra , "Paul E. McKenney" , Dave Jones , "linux-kernel@vger.kernel.org" Subject: Re: sched: circular dependency between sched_domains_mutex and oom_notify_list Message-ID: <20130218082639.GA15989@gmail.com> References: <51206DAB.7030701@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51206DAB.7030701@oracle.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 * Sasha Levin wrote: > I suspect it's the result of adding the new rcu_oom_notify, but that happened > about half a year ago so I'm not sure why this showed up only now. > > [ 1039.634183] ====================================================== > [ 1039.635717] [ INFO: possible circular locking dependency detected ] > [ 1039.637255] 3.8.0-rc7-next-20130215-sasha-00003-gea816fa #286 Tainted: G W > [ 1039.639104] ------------------------------------------------------- > [ 1039.640579] init/1 is trying to acquire lock: > [ 1039.641224] ((oom_notify_list).rwsem){.+.+..}, at: [] __blocking_notifier_call_chain+0x7f/0xc0 We changed (optimized) rwsems via: 3a15e0e0cdda rwsem: Implement writer lock-stealing for better scalability so maybe it can hit different codepaths and races now? Thanks, Ingo