[SCSI] fix oops in scsi_run_queue()

The recent commit closing the race window in device teardown: commit 86cbfb5 Author: James Bottomley <[email protected]> Date: Fri Apr 22 10:39:59 2011 -0500 [SCSI] put stricter guards on queue dead checks is causing a potential NULL deref in scsi_run_queue() because the q->queuedata may already be NULL by the time this function is called. Since we shouldn't be running a queue that is being torn down, simply add a NULL check in scsi_run_queue() to forestall this. Tested-by: Jim Schutt <[email protected]> Cc: [email protected] Signed-off-by: James Bottomley <[email protected]>
csanz · May 3, 2011 · c055f5b · c055f5b
1 parent 3fd9952
commit c055f5b
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
@@ -400,10 +400,15 @@ static inline int scsi_host_is_busy(struct Scsi_Host *shost)
 static void scsi_run_queue(struct request_queue *q)
 {
 	struct scsi_device *sdev = q->queuedata;
-	struct Scsi_Host *shost = sdev->host;
+	struct Scsi_Host *shost;
 	LIST_HEAD(starved_list);
 	unsigned long flags;
 
+	/* if the device is dead, sdev will be NULL, so no queue to run */
+	if (!sdev)
+		return;
+
+	shost = sdev->host;
 	if (scsi_target(sdev)->single_lun)
 		scsi_single_lun_run(sdev);