From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755051AbaELUBk (ORCPT ); Mon, 12 May 2014 16:01:40 -0400 Received: from mail-qc0-f169.google.com ([209.85.216.169]:43192 "EHLO mail-qc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752326AbaELUBj (ORCPT ); Mon, 12 May 2014 16:01:39 -0400 Date: Mon, 12 May 2014 16:01:35 -0400 From: Tejun Heo To: Sasha Levin Cc: LKML , Dave Jones , "Jason J. Herne" , Peter Zijlstra , Lai Jiangshan , Ingo Molnar Subject: Re: workqueue: WARN at at kernel/workqueue.c:2176 Message-ID: <20140512200135.GL1421@htj.dyndns.org> References: <537119EF.2060102@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <537119EF.2060102@oracle.com> 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 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) Hmm, this is "percpu worker on the wrong CPU while the current workqueue state indicates it should be on the CPU it's bound to" warning. We had a similar and more reproducible report a couple months back. http://lkml.kernel.org/g/52F4F01C.1070800@linux.vnet.ibm.com We added some debug code back then and it looked like the worker was setting the right cpus_allowed mask and the cpu was up but still ending up on the wrong CPU. Peter was looking into it and, ooh, I missed his last message and it fell through the crack. We probably should follow up on that thread. Thanks. -- tejun