Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754573Ab3ETKYi (ORCPT ); Mon, 20 May 2013 06:24:38 -0400 Received: from mail-ob0-f170.google.com ([209.85.214.170]:63547 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754105Ab3ETKYg (ORCPT ); Mon, 20 May 2013 06:24:36 -0400 MIME-Version: 1.0 In-Reply-To: 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> <5199ED83.5040804@linux.vnet.ibm.com> Date: Mon, 20 May 2013 15:54:35 +0530 Message-ID: Subject: Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule, round 2 From: Viresh Kumar To: Borislav Petkov Cc: "Srivatsa S. Bhat" , Frederic Weisbecker , Michael Wang , "Paul E. McKenney" , Jiri Kosina , Tony Luck , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , "Rafael J. Wysocki" , Linux PM mailing list , Tejun Heo Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1607 Lines: 39 On 20 May 2013 15:10, Viresh Kumar wrote: > On 20 May 2013 15:01, Srivatsa S. Bhat wrote: >> And Viresh, in the regular hotplug paths, the call to gov_cancel_work() is >> supposed to kill any pending workqueue functions pertaining to offline CPUs >> right? > > Yes.. It will cancel work for all cpus first and will start again for > online cpus again. > >> Could there be a synchronization bug somewhere due to which this >> might not be happening properly? > > Not sure.. I have seen mutex's are used well in cpufreq_governor.. don't know > if I missed something. Borislav, Can you try below change to see if the issue is still present? (Untested) diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 7532570..b9ae5f6 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -359,7 +359,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy, if (dbs_data->cdata->governor == GOV_CONSERVATIVE) cs_dbs_info->enable = 0; + mutex_lock(&cpu_cdbs->timer_mutex); gov_cancel_work(dbs_data, policy); + mutex_unlock(&cpu_cdbs->timer_mutex); mutex_lock(&dbs_data->mutex); mutex_destroy(&cpu_cdbs->timer_mutex); -- 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/