Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932219AbXAIQfN (ORCPT ); Tue, 9 Jan 2007 11:35:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932220AbXAIQfN (ORCPT ); Tue, 9 Jan 2007 11:35:13 -0500 Received: from CHOKECHERRY.SRV.CS.CMU.EDU ([128.2.185.41]:60627 "EHLO chokecherry.srv.cs.cmu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932219AbXAIQfL (ORCPT ); Tue, 9 Jan 2007 11:35:11 -0500 Message-ID: <45A3C420.8010708@cs.cmu.edu> Date: Tue, 09 Jan 2007 11:34:40 -0500 From: Benjamin Gilbert User-Agent: Thunderbird 1.5.0.7 (X11/20060916) MIME-Version: 1.0 To: Heiko Carstens CC: Srivatsa Vaddagiri , linux-kernel@vger.kernel.org, Ingo Molnar , Gautham shenoy , Andrew Morton Subject: Re: Failure to release lock after CPU hot-unplug canceled References: <20070108120719.16d4674e.bgilbert@cs.cmu.edu> <20070109121738.GC9563@osiris.boeblingen.de.ibm.com> <20070109122740.GC22080@in.ibm.com> <20070109150351.GD9563@osiris.boeblingen.de.ibm.com> In-Reply-To: <20070109150351.GD9563@osiris.boeblingen.de.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1433 Lines: 34 Heiko Carstens wrote: > On Tue, Jan 09, 2007 at 05:57:40PM +0530, Srivatsa Vaddagiri wrote: >> On Tue, Jan 09, 2007 at 01:17:38PM +0100, Heiko Carstens wrote: >>> The workqueue code grabs a lock on CPU_[UP|DOWN]_PREPARE and releases it >>> again on CPU_DOWN_FAILED/CPU_UP_CANCELED. If something in the callchain >>> returns NOTIFY_BAD the rest of the entries in the callchain won't be >>> called anymore. But DOWN_FAILED/UP_CANCELED will be called for every >>> entry. >>> So we might even end up with a mutex_unlock(&workqueue_mutex) even if >>> mutex_lock(&workqueue_mutex) hasn't been called... >> >> This is a known problem. Gautham had sent out patches to address them >> >> http://lkml.org/lkml/2006/11/14/93 >> >> Looks like they are in latest mm tree. Perhaps the testcase should be >> retried against latest mm. > > Ah, nice! Wasn't aware of that. But I still think we should have a > CPU_DOWN_FAILED in case CPU_DOWN_PREPARED failed. > Also the slab cache code hasn't been changed to make use of the of the > new CPU_LOCK_[ACQUIRE|RELEASE] stuff. I'm going to send patches in reply > to this mail. 2.6.20-rc3-mm1 plus your patches fixes it for me. Thanks --Benjamin Gilbert - 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/