From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761712AbYESNi4 (ORCPT ); Mon, 19 May 2008 09:38:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762169AbYESNXN (ORCPT ); Mon, 19 May 2008 09:23:13 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:33315 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762162AbYESNXM (ORCPT ); Mon, 19 May 2008 09:23:12 -0400 Date: Mon, 19 May 2008 15:22:50 +0200 From: Ingo Molnar To: Avi Kivity Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Make LIST_POISON less deadly Message-ID: <20080519132250.GA20793@elte.hu> References: <1211125094-32167-1-git-send-email-avi@qumranet.com> <20080519130151.GE13546@elte.hu> <48317E2B.2030304@qumranet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48317E2B.2030304@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'd suggest to add an ARCH_ILLEGAL_POINTER define instead, which >> defaults to zero and gets added to pointer-ish poison values. That >> makes it both simpler and also it does not need any include/asm >> changes because ARCH_ILLEGAL_POINTER can be set from the Kconfig >> space. > > Right. > > How much unmapped space do we have on i386 or other archs? The deltas > added to ARCH_ILLEGAL_POINTER will have to be limited to that. can we get away with having the offset default to zero, and all poison values remain unchanged if that? Then 64-bit x86 could just set the offset to 2^63 and we wont have to worry about 32-bit x86 at all ... i.e. start small with this and only have an effect on 64-bit x86. Ingo