diff --git a/ChangeLog b/ChangeLog
index 6001102c70..e999c2b22b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Jun 28 12:28:46 2003  Nobuyoshi Nakada  <nobu.nokada@softhome.net>
+
+	* gc.c (rb_gc_mark_locations): remove margin.  [ruby-dev:20462]
+
+	* gc.c (Init_stack): add safety margin.
+
 Fri May 30 11:25:58 2003  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* lib/irb/xmp.rb: sync with 1.8 ("irb/irb" -> "irb").
diff --git a/gc.c b/gc.c
index 12f210445a..3b3a3e3950 100644
--- a/gc.c
+++ b/gc.c
@@ -434,7 +434,7 @@ rb_gc_mark_locations(start, end)
 	start = end;
 	end = tmp;
     }
-    n = end - start + 1;
+    n = end - start;
     mark_locations_array(start,n);
 }
 
@@ -1106,11 +1106,11 @@ Init_stack(addr)
     if (!addr) addr = (VALUE *)&addr;
     if (rb_gc_stack_start) {
 	if (stack_growup_p(addr)) {
-	    if (rb_gc_stack_start > addr)
+	    if (rb_gc_stack_start > --addr)
 		rb_gc_stack_start = addr;
 	}
 	else {
-	    if (rb_gc_stack_start < addr)
+	    if (rb_gc_stack_start < ++addr)
 		rb_gc_stack_start = addr;
 	}
 	return;