From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752879AbaEMCSX (ORCPT ); Mon, 12 May 2014 22:18:23 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:42776 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751873AbaEMCSW (ORCPT ); Mon, 12 May 2014 22:18:22 -0400 Message-ID: <537180B9.6080407@oracle.com> Date: Mon, 12 May 2014 22:17:29 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Lai Jiangshan CC: Tejun Heo , LKML , Dave Jones , "Jason J. Herne" , 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> In-Reply-To: <53718119.1090000@cn.fujitsu.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/12/2014 10:19 PM, Lai Jiangshan wrote: > On 05/13/2014 04:01 AM, Tejun Heo wrote: >> > On Mon, May 12, 2014 at 02:58:55PM -0400, Sasha Levin wrote: >>> >> Hi all, >>> >> >>> >> While fuzzing with trinity inside a KVM tools guest running the latest -next >>> >> kernel I've stumbled on the following spew: >>> >> >>> >> [ 1297.886670] WARNING: CPU: 0 PID: 190 at kernel/workqueue.c:2176 process_one_work+0xb5/0x6f0() >>> >> [ 1297.889216] Modules linked in: >>> >> [ 1297.890306] CPU: 0 PID: 190 Comm: kworker/3:0 Not tainted 3.15.0-rc5-next-20140512-sasha-00019-ga20bc00-dirty #456 >>> >> [ 1297.893258] 0000000000000009 ffff88010c5d7ce8 ffffffffb153e1ec 0000000000000002 >>> >> [ 1297.893258] 0000000000000000 ffff88010c5d7d28 ffffffffae15fd6c ffff88010cdd6c98 >>> >> [ 1297.893258] ffff8806285d4000 ffffffffb3cd09e0 ffff88010cdde000 0000000000000000 >>> >> [ 1297.893258] Call Trace: >>> >> [ 1297.893258] dump_stack (lib/dump_stack.c:52) >>> >> [ 1297.893258] warn_slowpath_common (kernel/panic.c:430) >>> >> [ 1297.893258] warn_slowpath_null (kernel/panic.c:465) >>> >> [ 1297.893258] process_one_work (kernel/workqueue.c:2174 (discriminator 38)) >>> >> [ 1297.893258] worker_thread (kernel/workqueue.c:2354) >>> >> [ 1297.893258] kthread (kernel/kthread.c:210) >>> >> [ 1297.893258] ret_from_fork (arch/x86/kernel/entry_64.S:553) > Hi, > > I have been trying to address this bug. > Buy I can't reproduce this bug. Is your testing arch X86? > if yes, could you find out how to reproduce the bug? Yup, it's a 64bit KVM guest. 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? Thanks, Sasha