From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932275AbWCMEt7 (ORCPT ); Sun, 12 Mar 2006 23:49:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932302AbWCMEt7 (ORCPT ); Sun, 12 Mar 2006 23:49:59 -0500 Received: from smtp.osdl.org ([65.172.181.4]:17331 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932275AbWCMEt7 (ORCPT ); Sun, 12 Mar 2006 23:49:59 -0500 Date: Sun, 12 Mar 2006 20:47:36 -0800 From: Andrew Morton To: Neil Brown Cc: linux-kernel@vger.kernel.org Subject: Re: 2.6.16-rc6-mm1 (NFS tree ... busy inodes ... relatively harmless) Message-Id: <20060312204736.3102c314.akpm@osdl.org> In-Reply-To: <17428.63369.446803.958721@cse.unsw.edu.au> References: <20060312031036.3a382581.akpm@osdl.org> <17428.63369.446803.958721@cse.unsw.edu.au> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Neil Brown wrote: > > On Sunday March 12, akpm@osdl.org wrote: > > > > - The NFS tree is a bit sick - you may see the `busy inodes - self destruct > > in five seconds" message when performing NFS unmounts. It seems relatively > > harmless. > > I think the term is "mostly harmless" ... see the entry for "Earth" in > The Hitch-Hikers Guide To The Galaxy... :-) > > I don't believe this is harmless at all, and I have an oops to prove > it - though it is with NFSv4 which is still EXPERIMENTAL. > > I don't believe it is an NFS bug at all, but a VFS bug. It happens > more with NFS because iput on nfs can be a lot slower due to the > required network activity, so the race is easier to hit. It's 100% repeatable for me, with nfsv3 unmounts. First the busy inodes, then a use-after-free oops if CONFIG_DEBUG_PAGEALLOC (if that workaround patch I have in there isn't applied). Not a race, methinks.