From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Wang Subject: Re: [v3.10 regression] deadlock on cpu hotplug Date: Wed, 10 Jul 2013 14:04:50 +0800 Message-ID: <51DCF982.4070707@linux.vnet.ibm.com> References: <1443144.WnBWEpaopK@amdc1032> <51DB724F.9050708@linux.vnet.ibm.com> <1754044.EVIH1UZj6p@amdc1032> <51DC0B0D.9070201@linux.vnet.ibm.com> <51DCDF1C.1000208@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e28smtp03.in.ibm.com ([122.248.162.3]:35695 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750894Ab3GJGFD (ORCPT ); Wed, 10 Jul 2013 02:05:03 -0400 Received: from /spool/local by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 10 Jul 2013 11:28:33 +0530 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar Cc: "Srivatsa S. Bhat" , Bartlomiej Zolnierkiewicz , "Rafael J. Wysocki" , Borislav Petkov , Jiri Kosina , Tomasz Figa , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org On 07/10/2013 01:39 PM, Viresh Kumar wrote: > On 10 July 2013 09:42, Michael Wang wrote: >> I'm not sure what is supposed after notify CPUFREQ_GOV_STOP event, if it >> is in order to stop queued work and prevent follow work happen again, >> then it failed to, and we need some method to stop queue work again when >> CPUFREQ_GOV_STOP notified, like some flag in policy which will be >> checked before re-queue work in work. >> >> But if the event is just to sync the queued work but not prevent follow >> work happen, then things will become tough...we need confirm. > > After GOV_STOP, until the time GOV_START is called, we shouldn't be > queuing any work. Thanks for the confirm :) seems like the root cause is very likely related with the problem Srivatsa discovered. I think the fix in his mail worth a try, but I need more investigations to confirm that's the right way... 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/ >