diff --git a/drivers/usb/gadget/f_midi.c b/drivers/usb/gadget/f_midi.c
index 9c269c849882..dd6516100fa9 100644
--- a/drivers/usb/gadget/f_midi.c
+++ b/drivers/usb/gadget/f_midi.c
@@ -214,7 +214,9 @@ static struct usb_request *midi_alloc_ep_req(struct usb_ep *ep, unsigned length)
 
 static void midi_free_ep_req(struct usb_ep *ep, struct usb_request *req)
 {
+	WARN_ON(req->buf == NULL);
 	kfree(req->buf);
+	req->buf = NULL;
 	usb_ep_free_request(ep, req);
 }
 
@@ -379,7 +381,8 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 		if (err) {
 			ERROR(midi, "%s: couldn't enqueue request: %d\n",
 				    midi->out_ep->name, err);
-			midi_free_ep_req(midi->out_ep, req);
+			if (req->buf != NULL)
+				midi_free_ep_req(midi->out_ep, req);
 			return err;
 		}
 	}