From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754092AbdKFRx5 (ORCPT ); Mon, 6 Nov 2017 12:53:57 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:50040 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753810AbdKFRxz (ORCPT ); Mon, 6 Nov 2017 12:53:55 -0500 From: Colin King To: Jens Axboe , linux-block@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] block: avoid null pointer dereference on null disk Date: Mon, 6 Nov 2017 17:53:53 +0000 Message-Id: <20171106175353.20199-1-colin.king@canonical.com> X-Mailer: git-send-email 2.14.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King It is possible that the pointer disk can be null and hence we can get a null pointer deference when accessing disk->flags. Add a null pointer check to avoid the dereference. Detected by CoverityScan, CID#1461133 ("Explicit null dereferenced") Fixes: 8ddcd653257c ("block: introduce GENHD_FL_HIDDEN") Signed-off-by: Colin Ian King --- block/genhd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/genhd.c b/block/genhd.c index d85dcc701d76..42908a7186cd 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -798,7 +798,7 @@ struct gendisk *get_gendisk(dev_t devt, int *partno) spin_unlock_bh(&ext_devt_lock); } - if (unlikely(disk->flags & GENHD_FL_HIDDEN)) { + if (disk && unlikely(disk->flags & GENHD_FL_HIDDEN)) { put_disk(disk); disk = NULL; } -- 2.14.1