diff --git a/drivers/char/rocket.c b/drivers/char/rocket.c
index 79c3bc69165afb919f8084cf274c4d2310def8c2..7c79d243acc9b3fac68d6b4062fc9a43bb93eb65 100644
--- a/drivers/char/rocket.c
+++ b/drivers/char/rocket.c
@@ -1244,6 +1244,7 @@ static int set_config(struct tty_struct *tty, struct r_port *info,
 		}
 		info->flags = ((info->flags & ~ROCKET_USR_MASK) | (new_serial.flags & ROCKET_USR_MASK));
 		configure_r_port(tty, info, NULL);
+		mutex_unlock(&info->port.mutex);
 		return 0;
 	}