ublk: fail to recover device if queue setup is interrupted

In ublk_ctrl_end_recovery(), if wait_for_completion_interruptible() is
interrupted by signal, queues aren't setup successfully yet, so we
have to fail UBLK_CMD_END_USER_RECOVERY, otherwise kernel oops can be
triggered.

Fixes: c732a852 ("ublk_drv: add START_USER_RECOVERY and END_USER_RECOVERY support")
Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20230726144502.566785-3-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/ublk_drv.c

@@ -2324,7 +2324,9 @@ static int ublk_ctrl_end_recovery(struct ublk_device *ub,
 	pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
 			__func__, ub->dev_info.nr_hw_queues, header->dev_id);
 	/* wait until new ubq_daemon sending all FETCH_REQ */
-	wait_for_completion_interruptible(&ub->completion);
+	if (wait_for_completion_interruptible(&ub->completion))
+		return -EINTR;
+
 	pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n",
 			__func__, ub->dev_info.nr_hw_queues, header->dev_id);