From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752393AbaGWEVn (ORCPT ); Wed, 23 Jul 2014 00:21:43 -0400 Received: from mail-vc0-f174.google.com ([209.85.220.174]:52757 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbaGWEVl convert rfc822-to-8bit (ORCPT ); Wed, 23 Jul 2014 00:21:41 -0400 MIME-Version: 1.0 In-Reply-To: <53CF31AE.30403@daenzer.net> References: <53C77BB8.6030804@daenzer.net> <20140717075820.GE19379@twins.programming.kicks-ass.net> <53C8E90F.1010306@daenzer.net> <53CE00EF.70108@daenzer.net> <53CF31AE.30403@daenzer.net> Date: Tue, 22 Jul 2014 21:21:40 -0700 X-Google-Sender-Auth: o1j-Txjd01LXe4aOfk-8kzUVyzw Message-ID: Subject: Re: Random panic in load_balance() with 3.16-rc From: Linus Torvalds To: =?UTF-8?Q?Michel_D=C3=A4nzer?= Cc: Peter Zijlstra , Ingo Molnar , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 22, 2014 at 8:53 PM, Michel Dänzer wrote: > > Just happened again with the same change on top of 3.16-rc6. The (maybe) related bugzilla entry is just odd. Bruno Wolff reports that the BUG_ON() in his added patch triggers: + cpumask_clear(sched_group_cpus(sg)); + sg->sgc->capacity = 0; + BUG_ON(!cpumask_empty(sched_group_cpus(sg))); where it *just* did a cpumask_clear(), and now the BUG_ON() triggers that it's no longer empty? That would imply an allocation error, but all the sched groups seem to be properly allocated with the proper addition of cpumask_size(). And his config file even has NR_CPUS being 32, so it should be a single word of bitmap, which triggers all the simple code. Completely insane, in other words. Linus