From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756205Ab3KIPfj (ORCPT ); Sat, 9 Nov 2013 10:35:39 -0500 Received: from mail-qa0-f51.google.com ([209.85.216.51]:34123 "EHLO mail-qa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753785Ab3KIPfh (ORCPT ); Sat, 9 Nov 2013 10:35:37 -0500 From: Felipe Pena To: Konrad Rzeszutek Wilk , Boris Ostrovsky , David Vrabel Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, Felipe Pena Subject: [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference Date: Sat, 9 Nov 2013 13:36:09 -0200 Message-Id: <1384011369-4381-1-git-send-email-felipensp@gmail.com> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the blkif_release function the bdget_disk() call might returns a NULL ptr which might be dereferenced on bdev->bd_openers checking Signed-off-by: Felipe Pena --- drivers/block/xen-blkfront.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index a4660bb..7bb1552 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1959,6 +1959,9 @@ static void blkif_release(struct gendisk *disk, fmode_t mode) bdev = bdget_disk(disk, 0); + if (!bdev) + goto out_mutex; + if (bdev->bd_openers) goto out; @@ -1989,6 +1992,7 @@ static void blkif_release(struct gendisk *disk, fmode_t mode) out: bdput(bdev); +out_mutex: mutex_unlock(&blkfront_mutex); } -- 1.7.10.4