diff --git a/ChangeLog b/ChangeLog
index e1d252e28b..236645b53a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Jul 21 16:07:57 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/tracer.rb: toplevel caller exists now.  [ruby-core:24454]
+
 Tue Jul 21 13:36:20 2009  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.[ch] (recvmsg, sendmsg): new functions to support recvmsg/
diff --git a/lib/tracer.rb b/lib/tracer.rb
index 8e6586d7c6..5968971f87 100644
--- a/lib/tracer.rb
+++ b/lib/tracer.rb
@@ -161,6 +161,6 @@ if $0 == __FILE__
   ARGV.shift
   Tracer.on
   require $0
-elsif caller(0).size == 1
+elsif caller.size == 1
   Tracer.on
 end