From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756940AbaEPK3Y (ORCPT ); Fri, 16 May 2014 06:29:24 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:56298 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756807AbaEPK3X (ORCPT ); Fri, 16 May 2014 06:29:23 -0400 Date: Fri, 16 May 2014 12:29:08 +0200 From: Peter Zijlstra To: Lai Jiangshan Cc: jjherne@linux.vnet.ibm.com, Sasha Levin , Tejun Heo , LKML , Dave Jones , Ingo Molnar , Thomas Gleixner , Steven Rostedt Subject: Re: workqueue: WARN at at kernel/workqueue.c:2176 Message-ID: <20140516102908.GU30445@twins.programming.kicks-ass.net> References: <537119EF.2060102@oracle.com> <20140512200135.GL1421@htj.dyndns.org> <53718119.1090000@cn.fujitsu.com> <537180B9.6080407@oracle.com> <53739F3B.4060608@linux.vnet.ibm.com> <53758B12.8060609@cn.fujitsu.com> <20140516093530.GN11096@twins.programming.kicks-ass.net> <5375E0BA.7020208@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="e4HPWByEyAOAEWhK" Content-Disposition: inline In-Reply-To: <5375E0BA.7020208@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --e4HPWByEyAOAEWhK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 16, 2014 at 05:56:10PM +0800, Lai Jiangshan wrote: > On 05/16/2014 05:35 PM, Peter Zijlstra wrote: > > On Fri, May 16, 2014 at 11:50:42AM +0800, Lai Jiangshan wrote: > >> After debugging, I found the hotlug-in cpu is atctive but !online in t= his case. > >> the problem was introduced by 5fbd036b. > >> Some code assumes that any cpu in cpu_active_mask is also online, but = 5fbd036b breaks > >> this assumption, so the corresponding code with this assumption should= be changed too. > >=20 > > Good find, and yes it does that. > >=20 > >> The following patch is just a workaround. After it is applied, the abo= ve WARNING > >> is gone, but I can't hit the wq problem that you found. > >=20 > > Seeing how the entirety of hotplug is basically duct tape and twigs, the > > below isn't that bad. >=20 > I think we need to find a more grace solution... A complete rewrite of the hotplug mess, until that time this is fine. --e4HPWByEyAOAEWhK Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTdeh0AAoJEHZH4aRLwOS6+V4P/Rh65+O3nKEM9LZH2XuDrTLf 4EAk3MXpfNHOuJ/S87qWetCiIB2e9d33LJ9idXns/7pbUP4OqJf+imxTpQGuHQef JSvuqDCa5+BX1vEqjBA88+qlOuABvR0ayFOMMo6GGo1G7wg/DSEZ6IIgWRMqFo1q DhAWlG/oUmkUi/ADVeezmuRNXl/Ofkgk23y6ozQ9rGSfb1T2XY3xMP/zgq3q1f+s cThQmpsX/fUpoDZTZd2IkxrjYysYxKARvzSTqLfa3bMJZAeU1OpCNFvvoeuE9of9 1avg1NnTJlwFxYCZhlLVaCtGe5LjCb4NtCXYBwvcMwPczgjCrcBw/mwV7S1oJ9/I BO2IWbBzh9iMJTBo+AYfqh02uviklStNiW3wHaWXU0GawjFH8aMys3O2EyS8BL+X utRzaOqMiz68MWTl9eCOIpMn1cM+6lOMW8Q2d9onVs0OuFsT44+YC/8vOzr6/sFr BqFdDY1Pg1ypG5cBj8MWMXxPA0WinRkJzfWtQuA/YK1ASiKMOaXQGj+K4WQyT07j cRSqNPb1a13k9uxvDYLOMD4LluPR2ef5XlhQ4P2jkXgzCwJrOX9DBWl3tBiRxkqs 65fMLExxReqtf8lMPxGC6ciaiOmgtcX65MdL3HGpR6evl7RSe7v+kYMlHm8d5i/r whd57zD67p8bTOw7JMek =Poov -----END PGP SIGNATURE----- --e4HPWByEyAOAEWhK--