diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index a5719f271bf0..70ac1963b598 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -389,7 +389,8 @@ 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);
-			free_ep_req(midi->out_ep, req);
+			if (req->buf != NULL)
+				free_ep_req(midi->out_ep, req);
 			return err;
 		}
 	}
diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h
index 7d53a4773d1a..2f03334c6874 100644
--- a/drivers/usb/gadget/u_f.h
+++ b/drivers/usb/gadget/u_f.h
@@ -64,7 +64,9 @@ struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
 /* Frees a usb_request previously allocated by alloc_ep_req() */
 static inline void 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);
 }