From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964939AbcAUJwb (ORCPT ); Thu, 21 Jan 2016 04:52:31 -0500 Received: from mx2.suse.de ([195.135.220.15]:56221 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756718AbcAUJw0 (ORCPT ); Thu, 21 Jan 2016 04:52:26 -0500 Date: Thu, 21 Jan 2016 10:52:34 +0100 From: Jan Kara To: Shaohua Li Cc: Jan Kara , LKML , stable@vger.kernel.org, Tejun Heo , Daniel Bilik , Sasha Levin Subject: Re: Crashes with 874bbfe600a6 in 3.18.25 Message-ID: <20160121095234.GN10810@quack.suse.cz> References: <20160120211926.GJ10810@quack.suse.cz> <20160120213901.GA755895@devbig084.prn1.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160120213901.GA755895@devbig084.prn1.facebook.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Honza -- Jan Kara SUSE Labs, CR