diff --git a/drivers/tty/serial/mcf.c b/drivers/tty/serial/mcf.c
index a2e97c96e159..0edfaf8cd269 100644
--- a/drivers/tty/serial/mcf.c
+++ b/drivers/tty/serial/mcf.c
@@ -325,7 +325,9 @@ static void mcf_rx_chars(struct mcf_uart *pp)
 		uart_insert_char(port, status, MCFUART_USR_RXOVERRUN, ch, flag);
 	}
 
+	spin_unlock(&port->lock);
 	tty_flip_buffer_push(&port->state->port);
+	spin_lock(&port->lock);
 }
 
 /****************************************************************************/