--- x/sound/usb/midi.c
+++ y/sound/usb/midi.c
@@ -1145,6 +1145,11 @@ static int snd_usbmidi_output_open(struc
 
 static int snd_usbmidi_output_close(struct snd_rawmidi_substream *substream)
 {
+	if (substream->runtime &&
+	    substream->runtime->private_data) {
+		struct usbmidi_out_port *port = substream->runtime->private_data;
+		cancel_work_sync(&port->ep->work);
+	}
 	return substream_open(substream, 0, 0);
 }