From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 25 May 2001 10:09:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 25 May 2001 10:08:54 -0400 Received: from ns.suse.de ([213.95.15.193]:22798 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Fri, 25 May 2001 10:08:38 -0400 Date: Fri, 25 May 2001 16:07:29 +0200 From: Andi Kleen To: Oliver Neukum Cc: Keith Owens , Andreas Dilger , Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [CHECKER] large stack variables (>=1K) in 2.4.4 and 2.4.4-ac8 Message-ID: <20010525160729.B32273@gruyere.muc.suse.de> In-Reply-To: <24688.990773627@kao2.melbourne.sgi.com> <01052516035700.01561@idun> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <01052516035700.01561@idun>; from Oliver.Neukum@lrz.uni-muenchen.de on Fri, May 25, 2001 at 04:03:57PM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 25, 2001 at 04:03:57PM +0200, Oliver Neukum wrote: > > A small overflow of the kernel stack overwrites the struct task at the > > bottom of the stack, recovery is dubious at best because we rely on > > data in struct task. A large overflow of the kernel stack either > > corrupts the storage below this task's stack, which could hit anything, > > or it gets a stack fault. > > Is there a reason for the task structure to be at the bottom rather than the > top of these two pages ? This way you save one addition for every current access; which adds to quite a few KB over the complete kernel. -Andi