From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264392AbUADVst (ORCPT ); Sun, 4 Jan 2004 16:48:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264498AbUADVst (ORCPT ); Sun, 4 Jan 2004 16:48:49 -0500 Received: from fw.osdl.org ([65.172.181.6]:8845 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264392AbUADVsr (ORCPT ); Sun, 4 Jan 2004 16:48:47 -0500 Date: Sun, 4 Jan 2004 13:48:44 -0800 From: Andrew Morton To: Andrey Borzenkov Cc: linux-kernel@vger.kernel.org, proski@gnu.org, kpfleming@cox.net Subject: Re: [PATCH]: Fw: [Bugme-new] [Bug 1242] New: devfs oops with SMP kernel (not in UP mode) Message-Id: <20040104134844.1aa69452.akpm@osdl.org> In-Reply-To: <200401041932.40960.arvidjaar@mail.ru> References: <20030915212755.5017acc7.akpm@osdl.org> <200401041932.40960.arvidjaar@mail.ru> X-Mailer: Sylpheed version 0.9.4 (GTK+ 1.2.10; i686-pc-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 Andrey Borzenkov wrote: > > On Tuesday 16 September 2003 08:27, Andrew Morton wrote: > > Andrey, > > > > didn't we fix this? > > > > > > Sorry for delay. Oops is due to concurrent d_instantiate on the same dentry; > the bug was unfortunately quite ugly to fix inside devfs itself. Andrey, thanks for working on this. It is good to have a go-to guy for devfs problems. They all seem to be nasty nowadays. > The attached patch makes sure d_revalidate is always called under parent i_sem > allowing it to drop and reacquire semaphore before going to wait. It provides > both mutual exclusion with devfs_lookup and between d_revalidate, fixing Alas, people will have a heart-attack over the fs/namei.c changes. Is it not possible to add an additional semaphore into devfs to provide this exclusion? Are there any alternatives you can think of?