[SCSI] scsi_lib: fix potential NULL dereference

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.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 108655230b59..e495d3813948 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1359,9 +1359,9 @@ static int scsi_lld_busy(struct request_queue *q)
 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_target *starget = scsi_target(sdev);
-        struct Scsi_Host *shost = sdev->host;
+        struct scsi_device *sdev;
+        struct scsi_target *starget;
+        struct Scsi_Host *shost;
 
         blk_start_request(req);
 
@@ -1371,6 +1371,9 @@ static void scsi_kill_request(struct request *req, struct request_queue *q)
                 BUG();
         }
 
+        sdev = cmd->device;
+        starget = scsi_target(sdev);
+        shost = sdev->host;
         scsi_init_cmd_errh(cmd);
         cmd->result = DID_NO_CONNECT << 16;
         atomic_inc(&cmd->device->iorequest_cnt);