This patch adds a NULL check for the HCI UART ldisc driver because some
of HCI UART drivers allow hci_uart_tty_receive function to be called
even though the HCI device hasn't been registered yet.
Signed-off-by: Chan-yeol Park <chanyeol.park@samsung.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
 
        spin_lock(&hu->rx_lock);
        hu->proto->recv(hu, (void *) data, count);
-       hu->hdev->stat.byte_rx += count;
+
+       if (hu->hdev)
+               hu->hdev->stat.byte_rx += count;
+
        spin_unlock(&hu->rx_lock);
 
        tty_unthrottle(tty);