Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754110AbaJVOgV (ORCPT ); Wed, 22 Oct 2014 10:36:21 -0400 Received: from cantor2.suse.de ([195.135.220.15]:41929 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753679AbaJVOgR (ORCPT ); Wed, 22 Oct 2014 10:36:17 -0400 Date: Wed, 22 Oct 2014 16:36:14 +0200 (CEST) From: Jiri Kosina To: Daniel Lezcano cc: Peter Zijlstra , Ingo Molnar , "Rafael J. Wysocki" , Pavel Machek , Steven Rostedt , Dave Jones , "Paul E. McKenney" , Nicolas Pitre , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: lockdep splat in CPU hotplug In-Reply-To: <5447BEFE.2040806@linaro.org> Message-ID: References: <5447BEFE.2040806@linaro.org> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 22 Oct 2014, Daniel Lezcano wrote: > > > 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. > > > > > > What am I missing? > > > > Okay, reverting 442bf3aaf55a ("sched: Let the scheduler see CPU idle > > states") and followup 83a0a96a5f26 ("sched/fair: Leverage the idle state > > info when choosing the "idlest" cpu") which depends on it makes the splat > > go away. > > Are you able to reproduce it by offlining the cpu and onlining it again ? No, that doesn't trigger it (please note that all the relevant stacktraces from lockdep are going through hibernation). -- Jiri Kosina SUSE Labs -- 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/