diff --git a/ChangeLog b/ChangeLog
index ffc6e8309e..835cc59176 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Nov 12 19:47:29 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* thread.c (call_trace_proc): should return value.
+
 Mon Nov 12 19:45:18 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* {bcc,win}32/Makefile.sub (miniruby): use $(COMMONOBJS) and $(DMYEXT)
diff --git a/thread.c b/thread.c
index f059e0dc39..a80445dca8 100644
--- a/thread.c
+++ b/thread.c
@@ -2902,7 +2902,7 @@ call_trace_proc(VALUE args)
 	rb_thread_method_id_and_klass(GET_THREAD(), &id, &klass);
     }
     if (id == ID_ALLOCATOR)
-	return;
+	return Qnil;
     if (klass) {
 	if (TYPE(klass) == T_ICLASS) {
 	    klass = RBASIC(klass)->klass;