Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751747AbdIAJgc (ORCPT ); Fri, 1 Sep 2017 05:36:32 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53280 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558AbdIAJga (ORCPT ); Fri, 1 Sep 2017 05:36:30 -0400 Subject: Re: BUG: using __this_cpu_read() in preemptible [00000000] code: mm_percpu_wq/7 To: Tejun Heo , Heiko Carstens Cc: Christopher Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20170816091307.GA3102@osiris> <20170816142042.GB4087514@devbig577.frc2.facebook.com> From: Andre Wild Date: Fri, 1 Sep 2017 11:36:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20170816142042.GB4087514@devbig577.frc2.facebook.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 17090109-0040-0000-0000-000003D4EBA1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17090109-0041-0000-0000-000025D5649E Message-Id: <71a53bf8-3279-68db-3a95-b9e13c1fc73a@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-09-01_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1709010140 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2202 Lines: 55 On 08/16/2017 04:20 PM, Tejun Heo wrote: > Hello, > > On Wed, Aug 16, 2017 at 11:13:07AM +0200, Heiko Carstens wrote: >> [ 5968.010352] WARNING: CPU: 54 PID: 7 at kernel/workqueue.c:2041 process_one_work+0x6d4/0x718 >> >> (I don't remember we have seen the warning above in the first report) and then >> >> [ 5968.010913] Kernel panic - not syncing: preempt check >> [ 5968.010919] CPU: 54 PID: 7 Comm: mm_percpu_wq Tainted: G W 4.13.0-rc4-dirty #3 >> [ 5968.010923] Hardware name: IBM 3906 M03 703 (z/VM 6.4.0) >> [ 5968.010927] Workqueue: mm_percpu_wq vmstat_update >> [ 5968.010933] Call Trace: >> [ 5968.010937] ([<0000000000113fbe>] show_stack+0x8e/0xe0) >> [ 5968.010942] [<0000000000a514be>] dump_stack+0x96/0xd8 >> [ 5968.010947] [<000000000014302a>] panic+0x102/0x248 >> [ 5968.010952] [<00000000007836d8>] check_preemption_disabled+0xf8/0x110 >> [ 5968.010956] [<00000000002ee8e2>] refresh_cpu_vm_stats+0x1b2/0x400 >> [ 5968.010961] [<00000000002ef8be>] vmstat_update+0x2e/0x98 >> [ 5968.010965] [<0000000000166374>] process_one_work+0x3d4/0x718 >> [ 5968.010970] [<000000000016708c>] rescuer_thread+0x214/0x390 >> [ 5968.010974] [<000000000016edbc>] kthread+0x16c/0x180 >> [ 5968.010978] [<0000000000a7273a>] kernel_thread_starter+0x6/0xc >> [ 5968.010983] [<0000000000a72734>] kernel_thread_starter+0x0/0xc >> >> On cpu 54 we have mm_percpu_wq with: >> >> nr_cpus_allowed = 0x1, >> cpus_allowed = { >> bits = {0x4, 0x0, 0x0, 0x0} >> }, >> >> We also have CONFIG_NR_CPUS=256, so the above translates to cpu 3, which >> obviously is not cpu 54 and explains the preempt check warning. > > Looks like the same issue Paul was hitting. > > http://lkml.kernel.org/r/1501541603-4456-3-git-send-email-paulmck@linux.vnet.ibm.com > > Can you see whether the above patch helps? > > Thank.s > Hello, please excuse my late response. But I've found another kernel panic which stopped my test case execution each time. Now I've managed to work around the problem and it looks pretty good. With the patch I was not able to reproduce the problem within 24 hours runtime. Previously I could trigger it within 2-4 hours runtime. Kind regards André