From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756717Ab2ADSft (ORCPT ); Wed, 4 Jan 2012 13:35:49 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:35481 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756422Ab2ADSfr (ORCPT ); Wed, 4 Jan 2012 13:35:47 -0500 Message-ID: <1325702132.3037.100.camel@work-vm> Subject: Re: Regression: ONE CPU fails bootup at Re: [3.2.0-RC7] BUG: unable to handle kernel NULL pointer dereference at 0000000000000598 1.478005] IP: [] queue_work_on+0x4/0x30 From: John Stultz To: Stefan Bader Cc: NeilBrown , Konrad Rzeszutek Wilk , Sander Eikelenboom , rjw@sisk.pl, Thomas Gleixner , linux-kernel@vger.kernel.org Date: Wed, 04 Jan 2012 10:35:32 -0800 In-Reply-To: <4F04452C.7020209@canonical.com> References: <1599287628.20120103171351@eikelenboom.it> <20120103190754.GA27651@phenom.dumpdata.com> <1325632188.3037.59.camel@work-vm> <20120104113155.27bf6e46@notabene.brown> <1325638380.3037.69.camel@work-vm> <4F040B25.1080405@canonical.com> <4F04452C.7020209@canonical.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.1- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 x-cbid: 12010418-2398-0000-0000-0000032A70A5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-01-04 at 13:25 +0100, Stefan Bader wrote: > Which may point to execution of the irq worker (including a schedule_work) > before the rtc-cmos parts are finished... Would explain why moving the > initialize call further down does at least narrow the window for it to happen... > The only thing I do not understand then is why that seems only to happen on Xen > guests... Its just likely with Xen SMP guests that the race window is larger. I suspect similar behavior could be tripped on other slower SMP boxes as well. thanks -john