diff --git a/ChangeLog b/ChangeLog
index f28c904e8f..7f983a8377 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Aug 31 14:02:44 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_trace.c (rb_threadptr_exec_event_hooks): fix uninitialized state
+	  when no events is excuted.
+
 Thu Aug 30 18:21:51 2012  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (rb_io_close): call rb_last_status_clear.
diff --git a/vm_trace.c b/vm_trace.c
index 666d3d55e0..df07be6c9b 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -320,7 +320,7 @@ rb_threadptr_exec_event_hooks(rb_thread_t *th, rb_event_flag_t event, VALUE self
 {
     if (th->trace_running == 0 &&
 	self != rb_mRubyVMFrozenCore /* skip special methods. TODO: remove it. */) {
-	int state;
+	int state = 0;
 	int outer_state = th->state;
 	th->state = 0;