From 793bcd17d545d29175c9b7241cd5c6e408f7bc5f Mon Sep 17 00:00:00 2001
From: Marcel Moolenaar <marcel@FreeBSD.org>
Date: Thu, 30 Mar 2006 03:26:52 +0000
Subject: [PATCH] Don't open if we're going away.

---
 sys/dev/uart/uart_tty.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/dev/uart/uart_tty.c b/sys/dev/uart/uart_tty.c
index 601c377042f..df3d9eb3fd2 100644
--- a/sys/dev/uart/uart_tty.c
+++ b/sys/dev/uart/uart_tty.c
@@ -137,6 +137,10 @@ uart_tty_open(struct tty *tp, struct cdev *dev)
 	struct uart_softc *sc;
 
 	sc = tp->t_sc;
+
+	if (sc == NULL || sc->sc_leaving)
+		return (ENXIO);
+
 	sc->sc_opened = 1;
 	return (0);
 }