From 0993408c19b5f4d640a381f000f4c31d0b6bffcc Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Tue, 11 Oct 2011 16:40:54 -0600
Subject: [PATCH] fix `place-break' on terminated place

Merge to 5.2
---
 src/racket/src/place.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/racket/src/place.c b/src/racket/src/place.c
index deea9eebe7..2b901333e0 100644
--- a/src/racket/src/place.c
+++ b/src/racket/src/place.c
@@ -515,7 +515,7 @@ static int do_place_break(Scheme_Place *place)
   Scheme_Place_Object *place_obj;
   place_obj = place->place_obj;
 
-  {
+  if (place_obj) {
     mzrt_mutex_lock(place_obj->lock);
 
     place_obj->pbreak = 1;