diff --git a/ChangeLog b/ChangeLog
index 6a97a1d4e4..3b2b624998 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jun 13 14:19:09 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* gc.c (CHECK_STACK): STACK_LENGTH should be less than
+	  STACK_LEVEL_MAX.
+
 Thu Jun 12 21:05:44 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/openssl/ossl.h: include winsock.h if USE_WINSOCK2 is not defined.
diff --git a/gc.c b/gc.c
index 6199939ab6..a1df36cfa8 100644
--- a/gc.c
+++ b/gc.c
@@ -524,7 +524,7 @@ stack_grow_direction(addr)
 
 #define CHECK_STACK(ret) do {\
     SET_STACK_END;\
-    (ret) = (STACK_LENGTH > STACK_LEVEL_MAX + GC_WATER_MARK);\
+    (ret) = (STACK_LENGTH > STACK_LEVEL_MAX - GC_WATER_MARK);\
 } while (0)
 
 int
diff --git a/version.h b/version.h
index 39c4b2d55c..cc673f51bf 100644
--- a/version.h
+++ b/version.h
@@ -1,7 +1,7 @@
 #define RUBY_VERSION "1.8.7"
-#define RUBY_RELEASE_DATE "2008-06-12"
+#define RUBY_RELEASE_DATE "2008-06-13"
 #define RUBY_VERSION_CODE 187
-#define RUBY_RELEASE_CODE 20080612
+#define RUBY_RELEASE_CODE 20080613
 #define RUBY_PATCHLEVEL 5000
 
 #define RUBY_VERSION_MAJOR 1
@@ -9,7 +9,7 @@
 #define RUBY_VERSION_TEENY 7
 #define RUBY_RELEASE_YEAR 2008
 #define RUBY_RELEASE_MONTH 6
-#define RUBY_RELEASE_DAY 12
+#define RUBY_RELEASE_DAY 13
 
 #ifdef RUBY_EXTERN
 RUBY_EXTERN const char ruby_version[];