Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755774AbaJUPL1 (ORCPT ); Tue, 21 Oct 2014 11:11:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59811 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753403AbaJUPLZ (ORCPT ); Tue, 21 Oct 2014 11:11:25 -0400 Date: Tue, 21 Oct 2014 11:10:43 -0400 From: Dave Jones To: Jiri Kosina Cc: Peter Zijlstra , Ingo Molnar , "Rafael J. Wysocki" , Pavel Machek , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: lockdep splat in CPU hotplug Message-ID: <20141021151043.GA11800@redhat.com> Mail-Followup-To: Dave Jones , Jiri Kosina , Peter Zijlstra , Ingo Molnar , "Rafael J. Wysocki" , Pavel Machek , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 21, 2014 at 01:09:04PM +0200, Jiri Kosina wrote: > Hi, > > I am seeing the lockdep report below when resuming from suspend-to-disk > with current Linus' tree (c2661b80609). > > The reason for CCing Ingo and Peter is that I can't make any sense of one > of the stacktraces lockdep is providing. > > Please have a look at the very first stacktrace in the dump, where lockdep > is trying to explain where cpu_hotplug.lock#2 has been acquired. It seems > to imply that cpuidle_pause() is taking cpu_hotplug.lock, but that's not > the case at all. Could inlining be confusing the trace here ? You can get from cpuidle_pause to cpuidle_uninstall_idle_handler -> synchronize_rcu -> synchronize_sched -> synchronize_sched_expedited which does a try_get_online_cpus which will take the cpu_hotplug.lock Dave -- 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/