From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755098Ab2DKJJW (ORCPT ); Wed, 11 Apr 2012 05:09:22 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:59851 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751844Ab2DKJJU (ORCPT ); Wed, 11 Apr 2012 05:09:20 -0400 X-IronPort-AV: E=Sophos;i="4.75,405,1330876800"; d="scan'208";a="4730184" Message-ID: <4F854A60.7010704@cn.fujitsu.com> Date: Wed, 11 Apr 2012 17:09:52 +0800 From: Ren Mingxin User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20110412 CentOS/3.1.3-1.el6.centos Thunderbird/3.1.3 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: Rusty Russell , Kay Sievers , Tokunaga Kei , LKML , UDEV Subject: Re: [RFC PATCH] virtio_blk: Checking "private_data" to avoid kernel panic when hotplugging References: <4F728831.2090406@cn.fujitsu.com> <20120409075318.GB27771@redhat.com> <4F84F7BC.102@cn.fujitsu.com> <20120411083608.GC8562@redhat.com> In-Reply-To: <20120411083608.GC8562@redhat.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/04/11 17:08:41, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/04/11 17:08:43, Serialize complete at 2012/04/11 17:08:43 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/11/2012 04:36 PM, Michael S. Tsirkin wrote: > On Wed, Apr 11, 2012 at 11:17:16AM +0800, Ren Mingxin wrote: >> On 04/09/2012 03:53 PM, Michael S. Tsirkin wrote: >> >>> There's a chance you are hitting a race fixed by >>> 4678d6f970c2f7c0cbfefc0cc666432d153b321b. >>> >>> If it's still not fixed it might make sense to enable slab debugging - >>> we might have a use after free here. >>> >> I don't think the below commit has fixed this panic issue, for it is >> included >> in my last test environment(3.3-rc7). >> 4678d6f970c2f7c0cbfefc0cc666432d153b321b >> >> Now, I'd find which commit makes sense. > Great, thanks very much. I do suggest slab debugging if > the race reproduces for you with it enabled - reducing > the chance random struct rearrangements hide the bug. > Much appreciated for suggesting :-) I'll try it to locate the commit and backport it into rhel. -- Thanks, Ren