From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754861AbZJZH0F (ORCPT ); Mon, 26 Oct 2009 03:26:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754849AbZJZH0E (ORCPT ); Mon, 26 Oct 2009 03:26:04 -0400 Received: from brick.kernel.dk ([93.163.65.50]:34643 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754848AbZJZH0D (ORCPT ); Mon, 26 Oct 2009 03:26:03 -0400 Date: Mon, 26 Oct 2009 08:26:07 +0100 From: Jens Axboe To: Neil Brown Cc: Tejun Heo , linux-kernel@vger.kernel.org Subject: Re: [PATCH] use after free bug in __blkdev_get Message-ID: <20091026072607.GZ10727@kernel.dk> References: <19173.11702.129258.49993@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19173.11702.129258.49993@notabene.brown> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 26 2009, Neil Brown wrote: > > > commit 0762b8bde9729f10f8e6249809660ff2ec3ad735 > (from 14 months ago) introduced a use-after-free bug which has just > recently started manifesting in my md testing. > I tried git bisect to find out what caused the bug to start > manifesting, and it could have been the recent change to > blk_unregister_queue (48c0d4d4c04) but the results were inconclusive. > > This patch certainly fixes my symptoms and looks correct as the two > calls are now in the same order as elsewhere in that function. > > Signed-off-by: NeilBrown > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 9cf4b92..8bed055 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -1248,8 +1248,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) > bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); > } > } else { > - put_disk(disk); > module_put(disk->fops->owner); > + put_disk(disk); > disk = NULL; > if (bdev->bd_contains == bdev) { > if (bdev->bd_disk->fops->open) { Thanks Neil, good catch! Applied. -- Jens Axboe