From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756087AbZDXPHt (ORCPT ); Fri, 24 Apr 2009 11:07:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752654AbZDXPHl (ORCPT ); Fri, 24 Apr 2009 11:07:41 -0400 Received: from tomts40.bellnexxia.net ([209.226.175.97]:38836 "EHLO tomts40-srv.bellnexxia.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753078AbZDXPHk (ORCPT ); Fri, 24 Apr 2009 11:07:40 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApQFABtw8UlMQW1W/2dsb2JhbACBUM9Vg3QF Date: Fri, 24 Apr 2009 11:07:25 -0400 From: Mathieu Desnoyers To: Ingo Molnar Cc: Andrew Morton , Thomas Gleixner , gregkh@suse.de, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org Subject: Re: [BUG] 2.6.29.1 debugobjects warning Message-ID: <20090424150724.GA23568@Krystal> References: <20090423140002.GA12852@Krystal> <20090423164638.3b5769c6.akpm@linux-foundation.org> <20090424064937.GD21739@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20090424064937.GD21739@elte.hu> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 11:00:45 up 55 days, 11:26, 1 user, load average: 0.88, 0.50, 0.30 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar (mingo@elte.hu) wrote: > > * Andrew Morton wrote: > > > On Thu, 23 Apr 2009 10:00:02 -0400 > > Mathieu Desnoyers wrote: > > > > > ODEBUG: init active object type: timer_list > > > It seems to be complaining that cpufreq_governor_dbs() is running > > init_timer() against a timer which has already been initialised > > once. > > Not just already initialized - but also active. There's these states > for an object: > > ODEBUG_STATE_NONE, > ODEBUG_STATE_INIT, > ODEBUG_STATE_INACTIVE, > ODEBUG_STATE_ACTIVE, > ODEBUG_STATE_DESTROYED, > > So the 'init active object type' warning above suggests that an > init_timer() has been done on an already running timer. If true then > that is a bad bug - can corrupt timer state, etc. > > Thomas, do you agree? > This would fit with the behavior I've noticed and submitted a patch for later in this thread. Basically, the incorrect use of "cancel_delayed_work()" instead of "cancel_delayed_work_sync()" may leave the timer active if the race explained in the mail below happen. http://lkml.org/lkml/2009/4/24/19 Maybe we should audit other users of schedule_delayed_work/cancel_delayed_work that are re-arming themselves in the workqueue handler without any proper cancel_delayed_work_sync() nor flush_workqueue() calls on teardown. Mathieu > Ingo -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68