From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120205220952.826423599@pcw.home.local> Date: Sun, 05 Feb 2012 23:11:08 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jiri Slaby , James Bottomley , Greg KH Subject: [PATCH 79/91] SCSI: scsi_lib: fix potential NULL dereference In-Reply-To: <0635750f5f06ed2ca212b91fcb5c4483@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: 2.6.27-longterm review patch. If anyone has any objections, please let us know. ------------------ commit 03b147083a2f9a2a3fbbd2505fa88ffa3c6ab194 upstream. Stanse found a potential NULL dereference in scsi_kill_request. Instead of triggering BUG() in 'if (unlikely(cmd == NULL))' branch, the kernel will Oops earlier on cmd dereference. Move the dereferences after the if. [ WT: starget is not set in 2.6.27 ] Signed-off-by: Jiri Slaby Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/scsi_lib.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) Index: longterm-2.6.27/drivers/scsi/scsi_lib.c =================================================================== --- longterm-2.6.27.orig/drivers/scsi/scsi_lib.c 2012-02-05 22:34:42.697916475 +0100 +++ longterm-2.6.27/drivers/scsi/scsi_lib.c 2012-02-05 22:34:46.142917247 +0100 @@ -1389,8 +1389,8 @@ static void scsi_kill_request(struct request *req, struct request_queue *q) { struct scsi_cmnd *cmd = req->special; - struct scsi_device *sdev = cmd->device; - struct Scsi_Host *shost = sdev->host; + struct scsi_device *sdev; + struct Scsi_Host *shost; blkdev_dequeue_request(req); @@ -1400,6 +1400,8 @@ BUG(); } + sdev = cmd->device; + shost = sdev->host; scsi_init_cmd_errh(cmd); cmd->result = DID_NO_CONNECT << 16; atomic_inc(&cmd->device->iorequest_cnt);