diff --git a/ChangeLog b/ChangeLog
index 9760eb3b68..949050ece4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,6 @@
-Fri Aug 15 15:30:40 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Fri Aug 15 16:59:30 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_core.h (exec_event_hooks): skips RubyVM::FrozenCore.
 
 	* vm.c (Init_VM): get rid of SEGV in a trace proc.
 
diff --git a/vm_core.h b/vm_core.h
index 829ac4593e..2e8462422b 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -714,6 +714,7 @@ void rb_thread_execute_interrupts(rb_thread_t *);
 static inline void
 exec_event_hooks(rb_event_hook_t *hook, rb_event_flag_t flag, VALUE self, ID id, VALUE klass)
 {
+    if (self == rb_mRubyVMFrozenCore) return;
     while (hook) {
 	if (flag & hook->flag) {
 	    (*hook->func)(flag, hook->data, self, id, klass);