From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030242AbWCQSF1 (ORCPT ); Fri, 17 Mar 2006 13:05:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030245AbWCQSF1 (ORCPT ); Fri, 17 Mar 2006 13:05:27 -0500 Received: from silver.veritas.com ([143.127.12.111]:3336 "EHLO silver.veritas.com") by vger.kernel.org with ESMTP id S1030242AbWCQSF1 (ORCPT ); Fri, 17 Mar 2006 13:05:27 -0500 X-BrightmailFiltered: true X-Brightmail-Tracker: AAAAAA== X-IronPort-AV: i="4.03,105,1141632000"; d="scan'208"; a="36035570:sNHT24608768" Date: Fri, 17 Mar 2006 18:05:53 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: Christoph Lameter cc: linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: Race in pagevec_strip? In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-OriginalArrivalTime: 17 Mar 2006 18:05:26.0603 (UTC) FILETIME=[5E5F79B0:01C649ED] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 16 Mar 2006, Christoph Lameter wrote: > On Thu, 16 Mar 2006, Hugh Dickins wrote: > > > > But I should add, I don't see what might be racing with what on the > > same page, to cause the problem in practice. > > The page is on the inactive list at the time pagevec_strip is called > (see refill_inactive_zone). So kswapd could get to it. Could filesystems > get to the page via the mapping? A filesystem could get there, but I doubt it'd want to be releasing buffers. But now I see truncation's invalidate_complete_page, that looks quite capable of racing with the kswapd instance. Anyway, I don't disagree with your patch, and happy to see it now in Linus' tree: was just wanting to make clear that I hadn't actually seen the race in question, and didn't know if you were fixing a potentiality or something actually seen. Hugh