Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932886Ab2HIOAk (ORCPT ); Thu, 9 Aug 2012 10:00:40 -0400 Received: from smtp.ispras.ru ([83.149.198.202]:52415 "EHLO smtp.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932262Ab2HIN7Q (ORCPT ); Thu, 9 Aug 2012 09:59:16 -0400 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 09/13] ide: Potential null pointer dereference in set_multcount() Date: Thu, 9 Aug 2012 17:55:26 +0400 Message-Id: <1344520529-19164-7-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-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1380 Lines: 40 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-disk.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c index 16f69be..538d206 100644 --- a/drivers/ide/ide-disk.c +++ b/drivers/ide/ide-disk.c @@ -479,6 +479,10 @@ static int set_multcount(ide_drive_t *drive, int arg) return -EBUSY; rq = blk_get_request(drive->queue, READ, __GFP_WAIT); + if (!rq) { + printk(KERN_ERR PFX"set_multcount: blk_get_request() failed. \n"); + return 1; + } rq->cmd_type = REQ_TYPE_ATA_TASKFILE; drive->mult_req = arg; -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/