From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755332Ab1FPHlR (ORCPT ); Thu, 16 Jun 2011 03:41:17 -0400 Received: from out4.smtp.messagingengine.com ([66.111.4.28]:43204 "EHLO out4.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755083Ab1FPHAV (ORCPT ); Thu, 16 Jun 2011 03:00:21 -0400 X-Sasl-enc: Cyid3EklEpn5O3SEEXu+MX6xXiqD/NqgXzoHLC1/R+F5 1308207620 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Jun 15 17:02:30 2011 Message-Id: <20110616000230.377726335@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 15 Jun 2011 16:59:37 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Tejun Heo , Jens Axboe Subject: [14/89] block: blkdev_get() should access ->bd_disk only after In-Reply-To: <20110616000258.GA14529@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.39-stable review patch. If anyone has any objections, please let us know. ------------------ success From: Tejun Heo commit 4c49ff3fe128ca68dabd07537415c419ad7f82f9 upstream. d4dc210f69 (block: don't block events on excl write for non-optical devices) added dereferencing of bdev->bd_disk to test GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE; however, bdev->bd_disk can be %NULL if open failed which can lead to an oops. Test the flag after testing open was successful, not before. Signed-off-by: Tejun Heo Reported-by: David Miller Tested-by: David Miller Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/block_dev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1272,8 +1272,8 @@ int blkdev_get(struct block_device *bdev * individual writeable reference is too fragile given the * way @mode is used in blkdev_get/put(). */ - if ((disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE) && - !res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) { + if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && + (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { bdev->bd_write_holder = true; disk_block_events(disk); }