Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755105AbaDGT1W (ORCPT ); Mon, 7 Apr 2014 15:27:22 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:40482 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753771AbaDGT1U (ORCPT ); Mon, 7 Apr 2014 15:27:20 -0400 Message-ID: <5342FC08.5070106@fb.com> Date: Mon, 7 Apr 2014 15:27:04 -0400 From: Chris Mason User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Sasha Levin , , Jeff Mahoney , , , LKML Subject: Re: btrfs: lock inversion between delayed_node->mutex and found->groups_sem References: <53239AE0.8030306@oracle.com> <20140317130546.GE29256@twin.jikos.cz> <533307ED.8030700@suse.com> <533F20EB.2040500@oracle.com> <20140407165449.GA29256@twin.jikos.cz> <5342DD99.3010502@fb.com> <5342E86B.4000305@oracle.com> In-Reply-To: <5342E86B.4000305@oracle.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.16.4] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.11.96,1.0.14,0.0.0000 definitions=2014-04-07_03:2014-04-07,2014-04-07,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1404070176 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/07/2014 02:03 PM, Sasha Levin wrote: > On 04/07/2014 01:17 PM, Chris Mason wrote: >> >> >> On 04/07/2014 12:54 PM, David Sterba wrote: >>> On Fri, Apr 04, 2014 at 05:15:23PM -0400, Sasha Levin wrote: >>>> On 03/26/2014 01:01 PM, Jeff Mahoney wrote: >>>>> On 3/17/14, 9:05 AM, David Sterba wrote: >>>>>>> On Fri, Mar 14, 2014 at 08:12:16PM -0400, Sasha Levin wrote: >>>>>>>>> While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following: >>>>>>>>> >>>>>>>>> [ 788.458756] CPU0 CPU1 [ 788.459188] ---- ---- [ 788.459625] lock(&found->groups_sem); [ 788.460041] local_irq_disable(); [ 788.460041] lock(&delayed_node->mutex); [ 788.460041] lock(&found->groups_sem); [ 788.460041] [ 788.460041] lock(&delayed_node->mutex); [ 788.460041] [ 788.460041] *** DEADLOCK *** [ 788.460041] [ 788.460041] 2 locks held by kswapd3/4199: >>>>>>> >>>>>>> I've once (3.14-rc5) seen the same warning also caused by xfstests/generic/224 >>>>> I think this is from my sysfs patches. We call kobject_add while holding the group_sem. kobject_add ultimately allocates with GFP_KERNEL, so it can enter reclaim. This particular case isn't dangerous, but it could hit while hot-adding a device. The fix should be pretty simple. >>>> >>>> Is that fix available anywhere? I'm still seeing the issue in -next. >>> >>> It is: https://urldefense.proofpoint.com/v1/url?u=https://patchwork.kernel.org/patch/3894781/&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=6%2FL0lzzDhu0Y1hL9xm%2BQyA%3D%3D%0A&m=HQJVSK4wPTft1zWwI1cGvwj5OfdmN5UItVlucU1K31o%3D%0A&s=5113699a2e7345a779333c87dd5b1d88b4410a7c7fcd5fa424baeb838ad7d31b , will probably hit -rc2 >>> >> >> Its in the integration branch now along with some other important fixes. We'll get it out shortly > > Chris, > > Can I suggest adding the integration branch to linux-next as well? That way > all the folks who report issues coming out of -next would be able to test > the fixes as well. > Hi Sasha, The ink is still a little wet on the integration branch. It'll definitely go to linux-next and to Linus. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/