Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754206Ab3ETGrb (ORCPT ); Mon, 20 May 2013 02:47:31 -0400 Received: from mail.skyhub.de ([78.46.96.112]:42410 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753285Ab3ETGra (ORCPT ); Mon, 20 May 2013 02:47:30 -0400 Date: Mon, 20 May 2013 08:47:27 +0200 From: Borislav Petkov To: Michael Wang , Tejun Heo Cc: "Paul E. McKenney" , Jiri Kosina , Frederic Weisbecker , Tony Luck , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner Subject: Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule, round 2 Message-ID: <20130520064727.GD12690@pd.tnic> References: <20130509125040.GF27333@pd.tnic> <20130509125859.GG27333@pd.tnic> <20130515184528.GO4442@linux.vnet.ibm.com> <20130515224358.GF11783@pd.tnic> <20130515235512.GT4442@linux.vnet.ibm.com> <20130517135641.GF23035@pd.tnic> <51999591.8030401@linux.vnet.ibm.com> <20130520045023.GA12690@pd.tnic> <5199C169.7060504@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5199C169.7060504@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1431 Lines: 39 On Mon, May 20, 2013 at 02:23:37PM +0800, Michael Wang wrote: > On 05/20/2013 12:50 PM, Borislav Petkov wrote: > > On Mon, May 20, 2013 at 11:16:33AM +0800, Michael Wang wrote: > >> I suppose the reason is that the cpu we passed to > >> mod_delayed_work_on() has a chance to become offline before we > >> disabled irq, what about check it before send resched ipi? like: > > > > I think this is only addressing the symptoms - what we should be doing > > instead is asking ourselves why are we even scheduling work on a cpu if > > the machine goes offline? > > > > I don't know though who should be responsible for killing all that > > work - the workqueue itself or the guy who created it, i.e. cpufreq > > governor... > > So there are two questions here: > 1. Is gov_queue_work() want to queue the work on offline cpu? > 2. Is mod_delayed_work_on() allow offline cpu? > > I guess both should be false? Well, if we don't allow queueing work on a cpu which goes offline, i.e. #2, the problem should be solved. Tejun? Here are the splats: http://marc.info/?l=linux-kernel&m=136879901425951 -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- 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/