Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752838Ab3ETI5A (ORCPT ); Mon, 20 May 2013 04:57:00 -0400 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:33219 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751667Ab3ETI46 (ORCPT ); Mon, 20 May 2013 04:56:58 -0400 Message-ID: <5199E54D.7030407@linux.vnet.ibm.com> Date: Mon, 20 May 2013 16:56:45 +0800 From: Michael Wang User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Borislav Petkov CC: Viresh Kumar , Tejun Heo , "Paul E. McKenney" , Jiri Kosina , Frederic Weisbecker , Tony Luck , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , rjw@sisk.pl, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule, round 2 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> <20130520064727.GD12690@pd.tnic> <5199C990.3020602@linux.vnet.ibm.com> <5199CB59.1020309@linux.vnet.ibm.com> <5199CFD0.9030101@linux.vnet.ibm.com> In-Reply-To: <5199CFD0.9030101@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13052008-2674-0000-0000-000009091E0B Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2163 Lines: 73 On 05/20/2013 03:25 PM, Michael Wang wrote: [] > > Yeah, that's right, I guess the issue is, although the policy->cpus is > correct at a given time, after get cpu from it, it's possible to be > changed, unless we disabled preempt or irq, or hotplug before we use it... > > Like such issue cases: > get x from policy->cpus > DOWN notifier > change policy->cpus > do offline x > send ipi to x > > Will that happen? May be we could do some test to confirm it? diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 443442d..449be88 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -26,6 +26,7 @@ #include #include #include +#include #include "cpufreq_governor.h" @@ -180,8 +181,10 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, if (!all_cpus) { __gov_queue_work(smp_processor_id(), dbs_data, delay); } else { + get_online_cpus(); for_each_cpu(i, policy->cpus) __gov_queue_work(i, dbs_data, delay); + put_online_cpus(); } } EXPORT_SYMBOL_GPL(gov_queue_work); This is supposed to make WARN disappear, if it works, then BINGO :) Regards, Michael Wang > > Regards, > Michael Wang > > >> -- >> 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/ >> > > -- > 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/ > -- 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/