From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751135AbVKCGk3 (ORCPT ); Thu, 3 Nov 2005 01:40:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751140AbVKCGk3 (ORCPT ); Thu, 3 Nov 2005 01:40:29 -0500 Received: from dbl.q-ag.de ([213.172.117.3]:43713 "EHLO dbl.q-ag.de") by vger.kernel.org with ESMTP id S1751135AbVKCGk2 (ORCPT ); Thu, 3 Nov 2005 01:40:28 -0500 Message-ID: <4369B051.7050303@colorfullife.com> Date: Thu, 03 Nov 2005 07:38:09 +0100 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; U; Linux i686; fr-FR; rv:1.7.12) Gecko/20050923 Fedora/1.7.12-1.5.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Hugh Dickins CC: Dipankar Sarma , Linus Torvalds , Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: bad page state under possibly oom situation References: <20051102143502.GE6137@in.ibm.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hugh Dickins wrote: >(I don't know that it makes any difference, but was this particular report >from 2.6.9-rc2 or from 2.6.14 or from something else? In both 2.6.9 and >2.6.14, flags 0x90 mean PG_slab|PG_dirty.) > > > A very odd combination: - free_pages_check() ensures that neither PG_slab nor PG_dirty are set - prep_new_page() complains that both PG_slab and PG_dirty are set - AFAICS slab doesn't set PG_dirty, and noone except slab set PG_slab. I don't understand how two wrong bits can end up in page->flags. Dipankar, could you modify bad_page() and hexdump +-128 bytes? Perhaps someone overwrites random memory. Or change the value of PG_slab to 20 and check if page->flags remains 0x90. -- Manfred