From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755828AbdEKP2A (ORCPT ); Thu, 11 May 2017 11:28:00 -0400 Received: from gateway21.websitewelcome.com ([192.185.45.250]:26558 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752770AbdEKP1l (ORCPT ); Thu, 11 May 2017 11:27:41 -0400 Date: Thu, 11 May 2017 10:27:35 -0500 From: "Gustavo A. R. Silva" To: Konrad Rzeszutek Wilk , Roger Pau =?iso-8859-1?Q?Monn=E9?= , Juergen Gross Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] block: xen-blkback: add null check to avoid null pointer dereference Message-ID: <20170511152735.GA4409@embeddedgus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170511100544.Horde.88c0RhMPEXYq42BauaUXfHV@gator4166.hostgator.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.152.186.83 X-Exim-ID: 1d8q08-0002IY-9n X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedgus) [189.152.186.83]:40706 X-Source-Auth: garsilva@embeddedor.com X-Email-Count: 10 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add null check before calling xen_blkif_put() to avoid potential null pointer dereference. Addresses-Coverity-ID: 1350942 Cc: Juergen Gross Signed-off-by: Gustavo A. R. Silva --- drivers/block/xen-blkback/xenbus.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 8fe61b5..1f3dfaa 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -504,11 +504,13 @@ static int xen_blkbk_remove(struct xenbus_device *dev) dev_set_drvdata(&dev->dev, NULL); - if (be->blkif) + if (be->blkif) { xen_blkif_disconnect(be->blkif); - /* Put the reference we set in xen_blkif_alloc(). */ - xen_blkif_put(be->blkif); + /* Put the reference we set in xen_blkif_alloc(). */ + xen_blkif_put(be->blkif); + } + kfree(be->mode); kfree(be); return 0; -- 2.5.0