Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932289AbWE3OTa (ORCPT ); Tue, 30 May 2006 10:19:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932297AbWE3OTa (ORCPT ); Tue, 30 May 2006 10:19:30 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:39640 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932289AbWE3OT3 (ORCPT ); Tue, 30 May 2006 10:19:29 -0400 Subject: Re: [patch 00/61] ANNOUNCE: lock validator -V1 From: Arjan van de Ven To: Dave Jones Cc: Andrew Morton , linux-kernel@vger.kernel.org, Michal Piotrowski , Ingo Molnar In-Reply-To: <20060530141006.GG14721@redhat.com> References: <20060529212109.GA2058@elte.hu> <6bffcb0e0605291528qe24a0a3r3841c37c5323de6a@mail.gmail.com> <20060529224107.GA6037@elte.hu> <20060529230908.GC333@redhat.com> <1148967947.3636.4.camel@laptopd505.fenrus.org> <20060530141006.GG14721@redhat.com> Content-Type: text/plain Date: Tue, 30 May 2006 16:19:22 +0200 Message-Id: <1148998762.3636.65.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 35 On Tue, 2006-05-30 at 10:10 -0400, Dave Jones wrote: > On Tue, May 30, 2006 at 07:45:47AM +0200, Arjan van de Ven wrote: > > > One > > --- > > store_scaling_governor takes policy->lock and then calls __cpufreq_set_policy > > __cpufreq_set_policy calls __cpufreq_governor > > __cpufreq_governor calls __cpufreq_driver_target via cpufreq_governor_performance > > __cpufreq_driver_target calls lock_cpu_hotplug() (which takes the hotplug lock) > > > > > > Two > > --- > > cpufreq_stats_init lock_cpu_hotplug() and then calls cpufreq_stat_cpu_callback > > cpufreq_stat_cpu_callback calls cpufreq_update_policy > > cpufreq_update_policy takes the policy->lock > > > > > > so this looks like a real honest AB-BA deadlock to me... > > This looks a little clearer this morning. I missed the fact that sys_init_module > isn't completely serialised, only the loading part. ->init routines can and will be > called in parallel. > > I don't see where cpufreq_update_policy takes policy->lock though. > In my tree it just takes the per-cpu data->lock. isn't that basically the same lock? - 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/