In function bpa10x_send_frame() defined in file drivers/bluetooth/bpa10x.c, variable err takes the error code. When the call to usb_submit_urb() (at line 349) fails, a negative integer should be returned. However, it returns 0, which indicates that there is no error. Maybe it is better to "return err;" instead of "return 0;" at line 358. Codes related to this bug are summarised as follows.

283 static int bpa10x_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
284 {
285     struct bpa10x_data *data = hci_get_drvdata(hdev);
286     struct usb_ctrlrequest *dr;
287     struct urb *urb;
288     unsigned int pipe;
289     int err;
290 
291     BT_DBG("%s", hdev->name);
292 
293     skb->dev = (void *) hdev;
294 
295     urb = usb_alloc_urb(0, GFP_ATOMIC);
296     if (!urb)
297         return -ENOMEM;
        ...
349     err = usb_submit_urb(urb, GFP_ATOMIC);
350     if (err < 0) {
351         BT_ERR("%s urb %p submission failed", hdev->name, urb);
352         kfree(urb->setup_packet);
353         usb_unanchor_urb(urb);
354     }
355 
356     usb_free_urb(urb);
357 
358     return 0;      // return err?
359 }

Thanks very much!