Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964866AbWAIQfQ (ORCPT ); Mon, 9 Jan 2006 11:35:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964860AbWAIQfQ (ORCPT ); Mon, 9 Jan 2006 11:35:16 -0500 Received: from mx1.redhat.com ([66.187.233.31]:60854 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S964866AbWAIQfO (ORCPT ); Mon, 9 Jan 2006 11:35:14 -0500 Date: Mon, 9 Jan 2006 11:35:07 -0500 From: Dave Jones To: Linus Torvalds Cc: Linux Kernel Subject: Re: vm related lock up in 2.6.15 Message-ID: <20060109163507.GA20205@redhat.com> Mail-Followup-To: Dave Jones , Linus Torvalds , Linux Kernel References: <20060109021230.GA23750@redhat.com> <20060109154957.GA9766@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1024 Lines: 25 On Mon, Jan 09, 2006 at 08:32:20AM -0800, Linus Torvalds wrote: > > Turns out this was your BUG_ON(page_count(p) <= page_mapcount(p)); > > addition to putpage_test_zero, which I added a few days ago and promptly > > forgot about. > > > > Triggering this isn't too difficult it seems :-/ > > Well, as I warned in the message that had the patch, the test _is_ racy. > The reads of the page counts have no serialization, so if another process > is changing them, I don't guarantee that the test is correct. > > IOW, it was meant as a special case debug test for one particular problem > where I hoped it would give more information, rather than a real patch. ok, that explains. I'll go back to chasing the real cause of the corruption I was seeing :-/ Dave - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/