From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760403AbXJLREs (ORCPT ); Fri, 12 Oct 2007 13:04:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757240AbXJLREk (ORCPT ); Fri, 12 Oct 2007 13:04:40 -0400 Received: from mx1.redhat.com ([66.187.233.31]:55214 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755386AbXJLREj (ORCPT ); Fri, 12 Oct 2007 13:04:39 -0400 Date: Fri, 12 Oct 2007 18:04:34 +0100 From: Alasdair G Kergon To: Linus Torvalds Cc: dm-devel@redhat.com, linux-kernel@vger.kernel.org, "Bryn M. Reeves" Subject: [2.6.24 PATCH 01/25] dm mpath: rdac fix init race Message-ID: <20071012170434.GL24157@agk.fab.redhat.com> Mail-Followup-To: Linus Torvalds , dm-devel@redhat.com, linux-kernel@vger.kernel.org, "Bryn M. Reeves" Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Organization: Red Hat UK Ltd. Registered in England and Wales, number 04098903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Bryn M. Reeves Re-order the initialisation of dm-rdac to avoid registering the hw handler before the workqueue has been initialised. Closes a race that would potentially give an oops. Signed-off-by: Bryn M. Reeves Signed-off-by: Alasdair G Kergon --- drivers/md/dm-mpath-rdac.c | 15 ++++++++------- 1 files changed, 8 insertions(+), 7 deletions(-) Index: linux-2.6.23/drivers/md/dm-mpath-rdac.c =================================================================== --- linux-2.6.23.orig/drivers/md/dm-mpath-rdac.c 2007-10-12 13:15:23.000000000 +0100 +++ linux-2.6.23/drivers/md/dm-mpath-rdac.c 2007-10-12 13:15:24.000000000 +0100 @@ -664,20 +664,21 @@ static struct hw_handler_type rdac_handl static int __init rdac_init(void) { - int r = dm_register_hw_handler(&rdac_handler); - - if (r < 0) { - DMERR("%s: register failed %d", RDAC_DM_HWH_NAME, r); - return r; - } + int r; rdac_wkqd = create_singlethread_workqueue("rdac_wkqd"); if (!rdac_wkqd) { DMERR("Failed to create workqueue rdac_wkqd."); - dm_unregister_hw_handler(&rdac_handler); return -ENOMEM; } + r = dm_register_hw_handler(&rdac_handler); + if (r < 0) { + DMERR("%s: register failed %d", RDAC_DM_HWH_NAME, r); + destroy_workqueue(rdac_wkqd); + return r; + } + DMINFO("%s: version %s loaded", RDAC_DM_HWH_NAME, RDAC_DM_HWH_VER); return 0; }