From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765708AbYETMFA (ORCPT ); Tue, 20 May 2008 08:05:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753985AbYETMEt (ORCPT ); Tue, 20 May 2008 08:04:49 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:54190 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761651AbYETMEs (ORCPT ); Tue, 20 May 2008 08:04:48 -0400 Date: Tue, 20 May 2008 14:04:31 +0200 From: Ingo Molnar To: Avi Kivity Cc: Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Make LIST_POISON less deadly Message-ID: <20080520120431.GA9461@elte.hu> References: <1211125094-32167-1-git-send-email-avi@qumranet.com> <87k5hpgqwa.fsf@basil.nowhere.org> <4832B74F.5040402@qumranet.com> <4832BABA.9040809@firstfloor.org> <4832BB6A.8010809@qumranet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4832BB6A.8010809@qumranet.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Avi Kivity wrote: > I guess a fixmap would work for this. But then the offsets added to > that page would need to be limited to 4K. i dont think it's worth going for 32-bit here. On 32-bit the poison value gets skewed into hard to recognize values which might make oops analysis harder. Lets start small with 64-bit-only - there it's a quite plausible change, besides the exponentially larger address space on 64-bit it might realistically happen that an attacker can control a 32-bit-is offset but not a full 64-bit offset. Ingo