From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756246AbaENQwV (ORCPT ); Wed, 14 May 2014 12:52:21 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:45369 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755276AbaENQwS (ORCPT ); Wed, 14 May 2014 12:52:18 -0400 Message-ID: <53739F3B.4060608@linux.vnet.ibm.com> Date: Wed, 14 May 2014 12:52:11 -0400 From: "Jason J. Herne" Reply-To: jjherne@linux.vnet.ibm.com Organization: IBM User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Sasha Levin , Lai Jiangshan CC: Tejun Heo , LKML , Dave Jones , Peter Zijlstra , Ingo Molnar Subject: Re: workqueue: WARN at at kernel/workqueue.c:2176 References: <537119EF.2060102@oracle.com> <20140512200135.GL1421@htj.dyndns.org> <53718119.1090000@cn.fujitsu.com> <537180B9.6080407@oracle.com> In-Reply-To: <537180B9.6080407@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14051416-1344-0000-0000-0000018BBE63 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/12/2014 10:17 PM, Sasha Levin wrote: > I don't have an easy way to reproduce it as I only saw the bug once, but > it happened when I started pressuring CPU hotplug paths by adding and removing > CPUs often. Maybe it has anything to do with that? As per the original report (http://article.gmane.org/gmane.linux.kernel/1643027) I am able to reproduce the problem. The workload is (on S390 architecture): 2 processes onlining random cpus in a tight loop by using 'echo 1 > /sys/bus/cpu.../online' 2 processes offlining random cpus in a tight loop by using 'echo 0 > /sys/bus/cpu.../online' Otherwise, fairly idle system. load average: 5.82, 6.27, 6.27 The machine has 10 processors. The warning message some times hits within a few minutes on starting the workload. Other times it takes several hours. -- Jason J. Herne (jjherne@linux.vnet.ibm.com)