From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marina Makienko 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> References: <1344520529-19164-1-git-send-email-makienko@ispras.ru> Return-path: In-Reply-To: <1344520529-19164-1-git-send-email-makienko@ispras.ru> Sender: linux-kernel-owner@vger.kernel.org To: "David S. Miller" Cc: Marina Makienko , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@ispras.ru List-Id: 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; -- 1.7.7