From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755667Ab3F1KwF (ORCPT ); Fri, 28 Jun 2013 06:52:05 -0400 Received: from www.linutronix.de ([62.245.132.108]:45524 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755595Ab3F1KwC (ORCPT ); Fri, 28 Jun 2013 06:52:02 -0400 Date: Fri, 28 Jun 2013 12:52:02 +0200 (CEST) From: Thomas Gleixner To: Prarit Bhargava cc: Linux Kernel , athorlton@sgi.com, CAI Qian Subject: Re: BUG: tick device NULL pointer during system initialization and shutdown In-Reply-To: <51CC708B.7040605@redhat.com> Message-ID: References: <51C0AB09.2090605@redhat.com> <51CA2CBF.70404@redhat.com> <51CC708B.7040605@redhat.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 27 Jun 2013, Prarit Bhargava wrote: > On 06/26/2013 07:05 AM, Thomas Gleixner wrote: > > Subject: tick: Make oneshot broadcast robust vs. CPU offlining > > From: Thomas Gleixner > > Date: Wed, 26 Jun 2013 12:17:32 +0200 > > > > In periodic mode we remove offline cpus from the broadcast propagation > > mask. In oneshot mode we fail to do so. This was not a problem so far, > > but the recent changes to the broadcast propagation introduced a > > constellation which can result in a NULL pointer dereference. > > > > Unfortunately this patch causes an NMI watchdog during system shutdown. Most of > the CPUs are in start_secondary+0x254/0x256. Huch. Did the warning in the broadcast code trigger before that? Thanks, tglx