From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751485AbcAVBKp (ORCPT ); Thu, 21 Jan 2016 20:10:45 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:42289 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbcAVBKn (ORCPT ); Thu, 21 Jan 2016 20:10:43 -0500 Subject: Re: Crashes with 874bbfe600a6 in 3.18.25 To: Jan Kara , Shaohua Li , Tejun Heo References: <20160120211926.GJ10810@quack.suse.cz> <20160120213901.GA755895@devbig084.prn1.facebook.com> <20160121095234.GN10810@quack.suse.cz> Cc: LKML , stable@vger.kernel.org, Tejun Heo , Daniel Bilik From: Sasha Levin Message-ID: <56A1817C.10300@oracle.com> Date: Thu, 21 Jan 2016 20:10:20 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <20160121095234.GN10810@quack.suse.cz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/21/2016 04:52 AM, Jan Kara wrote: > On Wed 20-01-16 13:39:01, Shaohua Li wrote: >> On Wed, Jan 20, 2016 at 10:19:26PM +0100, Jan Kara wrote: >>> Hello, >>> >>> a friend of mine started seeing crashes with 3.18.25 kernel - once >>> appropriate load is put on the machine it crashes within minutes. He >>> tracked down that reverting commit 874bbfe600a6 (this is the commit ID from >>> Linus' tree, in stable tree the commit ID is 1e7af294dd03) "workqueue: make >>> sure delayed work run in local cpu" makes the kernel stable again. I'm >>> attaching screenshot of the crash - sadly the initial part is missing but >>> it seems that we crashed when processing timers on otherwise idle CPU. This >>> is a production machine so experimentation is not easy but if we really >>> need more information it may be possible to reproduce the issue again and >>> gather it. >>> >>> Anyone has idea what is going on? I was looking into the code for a while >>> but so far I have no good explanation. It would be good to understand the >>> cause instead of just blindly reverting the commit from stable tree... >> >> Tejun fixed a bug in timer: 22b886dd10180939. is it included in 3.18.25? > > That doesn't seem to be included in 3.18-stable although it was CCed to stable. > Sasha? Looks like it requires more than trivial backport (I think). Tejun? Thanks, Sasha