Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965031AbWIFXMY (ORCPT ); Wed, 6 Sep 2006 19:12:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964996AbWIFXCr (ORCPT ); Wed, 6 Sep 2006 19:02:47 -0400 Received: from mail.kroah.org ([69.55.234.183]:56780 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S964997AbWIFXCL (ORCPT ); Wed, 6 Sep 2006 19:02:11 -0400 Date: Wed, 6 Sep 2006 15:56:22 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, torvalds@osdl.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , akpm@osdl.org, alan@lxorguk.ukuu.org.uk, jeffm@suse.com, agk@redhat.com, Greg Kroah-Hartman Subject: [patch 14/37] dm: add module ref counting Message-ID: <20060906225622.GO15922@kroah.com> References: <20060906224631.999046890@quad.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="dm-add-module-ref-counting.patch" In-Reply-To: <20060906225444.GA15922@kroah.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1747 Lines: 62 -stable review patch. If anyone has any objections, please let us know. ------------------ From: Jeff Mahoney The reference counting on dm-mod is zero if no mapped devices are open. This is incorrect, and can lead to an oops if the module is unloaded while mapped devices exist. This patch claims a reference to the module whenever a device is created, and drops it again when the device is freed. Devices must be removed before dm-mod is unloaded. [akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled] Signed-off-by: Jeff Mahoney Signed-off-by: Alasdair G Kergon Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm.c | 6 ++++++ 1 file changed, 6 insertions(+) --- linux-2.6.17.11.orig/drivers/md/dm.c +++ linux-2.6.17.11/drivers/md/dm.c @@ -852,6 +852,9 @@ static struct mapped_device *alloc_dev(u return NULL; } + if (!try_module_get(THIS_MODULE)) + goto bad0; + /* get a minor number for the dev */ r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor); if (r < 0) @@ -918,6 +921,8 @@ static struct mapped_device *alloc_dev(u blk_cleanup_queue(md->queue); free_minor(minor); bad1: + module_put(THIS_MODULE); + bad0: kfree(md); return NULL; } @@ -941,6 +946,7 @@ static void free_dev(struct mapped_devic put_disk(md->disk); blk_cleanup_queue(md->queue); + module_put(THIS_MODULE); kfree(md); } -- - 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/