From patchwork Thu Aug 9 13:55:28 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marina Makienko X-Patchwork-Id: 176104 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E760B2C00CE for ; Thu, 9 Aug 2012 23:59:40 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030227Ab2HIN7T (ORCPT ); Thu, 9 Aug 2012 09:59:19 -0400 Received: from smtp.ispras.ru ([83.149.198.202]:52431 "EHLO smtp.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932653Ab2HIN7S (ORCPT ); Thu, 9 Aug 2012 09:59:18 -0400 Received: from torvalds.intra.ispras.ru (unknown [83.149.198.253]) by smtp.ispras.ru (Postfix) with ESMTP id 251825D4042; Thu, 9 Aug 2012 17:23:51 +0400 (MSD) From: Marina Makienko To: "David S. Miller" Cc: Marina Makienko , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@ispras.ru Subject: [PATCH 11/13] ide: Potential null pointer dereference in idetape_queue_rw_tail() Date: Thu, 9 Aug 2012 17:55:28 +0400 Message-Id: <1344520529-19164-9-git-send-email-makienko@ispras.ru> X-Mailer: git-send-email 1.7.7 In-Reply-To: <1344520529-19164-1-git-send-email-makienko@ispras.ru> References: <1344520529-19164-1-git-send-email-makienko@ispras.ru> Sender: linux-ide-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org The function blk_get_request() can return NULL in some cases. There are checks on it if function is called with argumetns one of which is GFP_ATOMIC/GFP_NOIO/etc. If system couldn't find request blk_get_request() return NULL. But if there is function call with argument __GFP_WAIT the system will wait until get request or the queue becomes dead. If something kills the queue, blk_get_request() return NULL and next operations will lead to errors. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Marina Makienko --- drivers/ide/ide-tape.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c index ce8237d..c27b05c 100644 --- a/drivers/ide/ide-tape.c +++ b/drivers/ide/ide-tape.c @@ -853,6 +853,8 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int size) BUG_ON(size < 0 || size % tape->blk_size); rq = blk_get_request(drive->queue, READ, __GFP_WAIT); + if (!rq) + return -EIO; rq->cmd_type = REQ_TYPE_SPECIAL; rq->cmd[13] = cmd; rq->rq_disk = tape->disk;