From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756316AbcIGT0e (ORCPT ); Wed, 7 Sep 2016 15:26:34 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:34994 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752829AbcIGT0c (ORCPT ); Wed, 7 Sep 2016 15:26:32 -0400 Subject: Re: [writeback] 8bc4ad9498: INFO: suspicious RCU usage. ] To: Tejun Heo , kernel test robot References: <57c8012a.zlFYe5dba5wTaKD+%xiaolong.ye@intel.com> <20160907164103.GA1375@htj.duckdns.org> CC: , Jens Axboe , LKML From: Jens Axboe Message-ID: <6046dded-a2a6-b6e2-8c2c-0cf13accf1e9@fb.com> Date: Wed, 7 Sep 2016 13:25:54 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160907164103.GA1375@htj.duckdns.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit 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1;CY4PR15MB1192;20:mdu342fkDWc5OAOrnWt5TkdBFJ/esjprnuE9zUQrlhiqeKOEEHEmknHiCiGWO1Z06ZRtiR10LBkwuCaqTLm6rZBXx7TlnGOOykfJ6F1XBmwhfPUIMmG4CRTsq5So+qJUFD1TGQGP1pu4XSdrAf/9BtAjmhphMrhmp49rId84Pzg= X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Sep 2016 19:26:03.1171 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR15MB1192 X-OriginatorOrg: fb.com X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-09-07_07:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/07/2016 10:41 AM, Tejun Heo wrote: > On Thu, Sep 01, 2016 at 06:21:30PM +0800, kernel test robot wrote: >> >> FYI, we noticed the following commit: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git wb-buf-throttle >> commit 8bc4ad9498f81d6689da42457615db0989e720d3 ("writeback: throttle buffered writeback") >> >> in testcase: boot >> >> on test machine: qemu-system-x86_64 -enable-kvm -cpu Westmere -m 512M >> >> caused below changes: >> >> >> +--------------------------------------+------------+------------+ >> | | b2e4e4e34d | 8bc4ad9498 | >> +--------------------------------------+------------+------------+ >> | boot_successes | 6 | 0 | >> | boot_failures | 0 | 8 | >> | INFO:suspicious_RCU_usage | 0 | 8 | >> | message:INFO:suspicious_RCU_usage | 0 | 0.0 | >> | pattern:INFO:suspicious_RCU_usage | 0 | 0 | >> | calltrace:disk_events_workfn | 0 | 8 | >> | message:calltrace:disk_events_workfn | 0 | 0.0 | >> | pattern:calltrace:disk_events_workfn | 0 | 0 | >> +--------------------------------------+------------+------------+ >> >> >> >> [ 7.389264] stack backtrace: >> [ 7.391300] CPU: 0 PID: 19 Comm: kworker/0:1 Not tainted 4.8.0-rc4-00008-g8bc4ad9 #1 >> [ 7.395279] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 >> [ 7.398012] Workqueue: events_freezable_power_ disk_events_workfn >> [ 7.399933] 0000000000000000 ffff88003db1f8e8 ffffffff8178ed3b ffff88003db184c0 >> [ 7.404348] 0000000000000001 ffff88003db1f918 ffffffff81123472 ffff88003db184c0 >> [ 7.407158] ffffffff84091180 0000000000000003 ffff880039d4c400 ffff88003db1f938 >> [ 7.410074] Call Trace: >> [ 7.411328] [] dump_stack+0x82/0xb8 >> [ 7.413982] [] lockdep_rcu_suspicious+0xf7/0x100 >> [ 7.415828] [] bio_blkcg+0x89/0x93 >> [ 7.417336] [] check_blkcg_changed+0x58/0x1b8 > > Hmm... can't reproduce here on qemu with v4.8-rc5 and the same kernel > config. Can you please check whether it reproduces on v4.8-rc5? If > so, is there any way I can get the qemu image and command line used? I've been getting them for a while. I just updated the branch to -rc5 this morning, so if it does reproduce, the same mail would likely show up again. I'll keep you posted :-) The command line was in the original email: $ qemu-system-x86_64 -enable-kvm -cpu Westmere -m 512M And agree, in general it'd be nice if there was a link to the image as well, so that folks can reproduce. -- Jens Axboe