Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752767AbaBSDMX (ORCPT ); Tue, 18 Feb 2014 22:12:23 -0500 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:58026 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752059AbaBSDMW (ORCPT ); Tue, 18 Feb 2014 22:12:22 -0500 Message-ID: <5304210B.9060604@linux.vnet.ibm.com> Date: Wed, 19 Feb 2014 11:12:11 +0800 From: Michael wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Peter Zijlstra CC: paulus@samba.org, Ingo Molnar , acme@ghostprotocols.net, Thomas Gleixner , "H. Peter Anvin" , x86@kernel.org, LKML Subject: Re: [BUG] sched: tip/master show panic while booting/rebooting References: <5302EBA3.10909@linux.vnet.ibm.com> <20140218112230.GA27965@twins.programming.kicks-ass.net> In-Reply-To: <20140218112230.GA27965@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14021903-5816-0000-0000-00000C58E7EC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/18/2014 07:22 PM, Peter Zijlstra wrote: > On Tue, Feb 18, 2014 at 01:12:03PM +0800, Michael wang wrote: >> Hi, Folks >> >> Got below panic while testing tip/master on x86 box, it randomly >> occur while booting or rebooting, any ideas? > > The obvious pick would be the relocation of the idle_balance call, but > I'm not sure how that'll end up stalling. I've review the code again, seems like it was caused by the same issue we discussed (RT/DL enqueued issue), I found that idle_balance() will return 1 in such cases: /* * While browsing the domains, we released the rq lock. * A task could have be enqueued in the meantime */ if (this_rq->nr_running && !pulled_task) return 1; And if no more fair task to be pulled, we will do balance again and again in pick_next_task_fair() until panic in NMI... The solution we discussed could solve the problem I suppose, it was already in progress, correct? Please let me know if there are any thing I could help with ;-) 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/