Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752817AbaJGB16 (ORCPT ); Mon, 6 Oct 2014 21:27:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:14723 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752640AbaJGB14 (ORCPT ); Mon, 6 Oct 2014 21:27:56 -0400 Date: Mon, 6 Oct 2014 21:27:44 -0400 From: Dave Jones To: Tejun Heo Cc: "Paul E. McKenney" , Linux Kernel Subject: Re: RCU stalls -> lockup. Message-ID: <20141007012744.GA25036@redhat.com> Mail-Followup-To: Dave Jones , Tejun Heo , "Paul E. McKenney" , Linux Kernel References: <20141002175515.GA28665@redhat.com> <20141002193655.GS5015@linux.vnet.ibm.com> <20141005021556.GC8549@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141005021556.GC8549@htj.dyndns.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 04, 2014 at 10:15:56PM -0400, Tejun Heo wrote: > On Thu, Oct 02, 2014 at 12:36:55PM -0700, Paul E. McKenney wrote: > > On Thu, Oct 02, 2014 at 01:55:15PM -0400, Dave Jones wrote: > > > I just hit this on my box running 3.17rc7 > > > It was followed by a userspace lockup. (Could still ping, and sysrq > > > from the console, but even getty wasn't responding on the console). > > > > > > I was trying to reproduce another bug faster, and had ramped up the > > > number of processes trinity to uses to 512. This didn't take long > > > to fall out.. > > > > This might be related to an exchange I had with Tejun (CCed), where > > the work queues were running all out, preventing any quiescent states > > from happening. One fix under consideration is to add a quiescent state, > > similar to the one in softirq handling. > > Dave, can you please test whether the following patch makes a > difference if the problem is reproducible? > > http://lkml.kernel.org/r/20141003153701.7c7da030@jlaw-desktop.mno.stratus.com initial tests look good, haven't seen any reoccurance of the problem so far. Dave -- 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/