From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161500AbWAMIps (ORCPT ); Fri, 13 Jan 2006 03:45:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161501AbWAMIps (ORCPT ); Fri, 13 Jan 2006 03:45:48 -0500 Received: from mtagate4.de.ibm.com ([195.212.29.153]:53747 "EHLO mtagate4.de.ibm.com") by vger.kernel.org with ESMTP id S1161500AbWAMIps (ORCPT ); Fri, 13 Jan 2006 03:45:48 -0500 Subject: Re: [patch 5/13] s390: show_task oops. From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com To: Andrew Morton Cc: heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org In-Reply-To: <20060112165826.5843e34c.akpm@osdl.org> References: <20060112171516.GF16629@skybase.boeblingen.de.ibm.com> <20060112165826.5843e34c.akpm@osdl.org> Content-Type: text/plain Date: Fri, 13 Jan 2006 09:45:42 +0100 Message-Id: <1137141942.6192.5.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.4.2.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2006-01-12 at 16:58 -0800, Andrew Morton wrote: > Martin Schwidefsky wrote: > > > > From: Heiko Carstens > > > > [patch 5/13] s390: show_task oops. > > > > The show_task function walks the kernel stack backchain of > > processes assuming that the processes are not running. Since > > this assumption is not correct walking the backchain can lead > > to an addressing exception and therefore to a kernel hang. > > So prevent the kernel hang (you still get incorrect results) > > verity that all read accesses are within the bounds of the > > kernel stack before performing them. > > > > This one needs to be thought about and tested versus the just-merged > s390-task_stack_page.patch. I guess it'll still work, but some of the > pretty new accessors could be used in there, at least. Oh yes, didn't notice that Al Viro's task_thread_info() changes got merged in the meantime. We'll test & send a follow-up patch. -- blue skies, Martin Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH