scsi: tcmu: fix use after free

Fixes: a94a2572 ("scsi: tcmu: avoid cmd/qfull timers updated whenever a new cmd comes")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Mike Christie <mchristi@redhat.com>
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_user.c

@@ -1317,12 +1317,13 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data)
 		 * target_complete_cmd will translate this to LUN COMM FAILURE
 		 */
 		scsi_status = SAM_STAT_CHECK_CONDITION;
+		list_del_init(&cmd->queue_entry);
 	} else {
+		list_del_init(&cmd->queue_entry);
 		idr_remove(&udev->commands, id);
 		tcmu_free_cmd(cmd);
 		scsi_status = SAM_STAT_TASK_SET_FULL;
 	}
-	list_del_init(&cmd->queue_entry);
 
 	pr_debug("Timing out cmd %u on dev %s that is %s.\n",
 		 id, udev->name, is_running ? "inflight" : "queued");