From 122ca9b7cddf75a5d37623c64261d1929b64e6e4 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Sat, 29 Dec 2012 06:26:47 -0800
Subject: [PATCH] Fix potential attach order bug when attaching a serial port
 to a single line mux found by Dave Bryan

---
 sim_tmxr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sim_tmxr.c b/sim_tmxr.c
index 966bfd84..36093e47 100644
--- a/sim_tmxr.c
+++ b/sim_tmxr.c
@@ -1641,7 +1641,7 @@ while (*tptr) {
             serport = sim_open_serial (destination, lp, &r);
             if (serport != INVALID_HANDLE) {
                 _mux_detach_line (lp, TRUE, TRUE);
-                if (lp->mp->master) {                       /* if existing listener, close it */
+                if (lp->mp && lp->mp->master) {             /* if existing listener, close it */
                     sim_close_sock (lp->mp->master, 1);
                     lp->mp->master = 0;
                     free (lp->mp->port);