Specifically set the cancellable state for it to not be uninitialised in the usb transfer struct.
diff --git a/usbutils.c b/usbutils.c
index 6fe3e63..232e19f 100644
--- a/usbutils.c
+++ b/usbutils.c
@@ -2313,7 +2313,8 @@ static int usb_submit_transfer(struct usb_transfer *ut, struct libusb_transfer *
ut->cancellable = true;
INIT_LIST_HEAD(&ut->ct.list);
list_add(&ct_list, &ut->ct.list);
- }
+ } else
+ ut->cancellable = false;;
cg_wunlock(&cgusb_fd_lock);
return err;