From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759802AbXLQN25 (ORCPT ); Mon, 17 Dec 2007 08:28:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754347AbXLQN2t (ORCPT ); Mon, 17 Dec 2007 08:28:49 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:54380 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755472AbXLQN2t (ORCPT ); Mon, 17 Dec 2007 08:28:49 -0500 Date: Mon, 17 Dec 2007 14:28:02 +0100 From: Ingo Molnar To: Jan Beulich Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, Andi Kleen , linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH] x86: fix ref-counting bug in change_page_attr() Message-ID: <20071217132802.GD1870@elte.hu> References: <47610AB5.76E4.0078.0@novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47610AB5.76E4.0078.0@novell.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 * Jan Beulich wrote: > When either calling change_page_attr() with the default attributes > pages in the direct mapping have and a page's attributes already were > set to the default or when changing the attributes from one > non-default value to another, the reference counting broke, leading to > either premature restoration of a large page or missing the > opportunity to do so. > > At the same time, make __PHYSICAL_MASK_SHIFT on 64-bits the value it > architecturally ought to have. hm, does this patch fix any real bug seen live? (if yes then do you have links to it, etc?) It would be a v2.6.24 fix in theory but it looks too dangerous for that. So i've queued it up for v2.6.25, for the time being. Ingo