From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756836AbcBDM11 (ORCPT ); Thu, 4 Feb 2016 07:27:27 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:38334 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753208AbcBDM1Z (ORCPT ); Thu, 4 Feb 2016 07:27:25 -0500 Message-ID: <1454588837.3407.148.camel@gmail.com> Subject: Re: crash in 3.12.51 (likely in 3.12.52 as well) in timer code From: Mike Galbraith To: Nikolay Borisov , "Linux-Kernel@Vger. Kernel. Org" Cc: Jiri Slaby , Oleg Nesterov , tglx@linutronix.de, SiteGround Operations Date: Thu, 04 Feb 2016 13:27:17 +0100 In-Reply-To: <56B34233.5010804@kyup.com> References: <56B1DD62.9030900@kyup.com> <1454585550.3407.126.camel@gmail.com> <56B33B34.6090508@kyup.com> <1454588264.3407.142.camel@gmail.com> <56B34233.5010804@kyup.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2016-02-04 at 14:21 +0200, Nikolay Borisov wrote: > > > On a different note - is there a way to safely reproduce this so I can > > > test the suggested fix by Thomas? > > > > Hm, write a module to beat mod_delayed_work() to pulp with a NR_CPUS > > horde, and run it in a vm where you don't care about shrapnel? > > In other words, have multiple threads (NR_CPUS) that spin on > mod_delayed_work? Yeah, give threads lots of opportunities to collide. (not forgetting to sleep at least occasionally;) -Mike