diff --git a/ChangeLog b/ChangeLog
index 40062b5c6a..6e70a47b73 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun May 16 22:21:32 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* proc.c (mnew): initialize a field.  a patch from Takahiro Kambe.
+	  [ruby-dev:41312]
+
 Sun May 16 22:17:35 2010  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* eval.c (setup_exception): let SystemStackError#backtrace return an
diff --git a/proc.c b/proc.c
index b4ecd576c8..9d4a527a1c 100644
--- a/proc.c
+++ b/proc.c
@@ -914,6 +914,7 @@ mnew(VALUE klass, VALUE obj, ID id, VALUE mclass, int scope)
 		def->alias_count = 0;
 
 		meb.flag = 0;
+		meb.mark = 0;
 		meb.called_id = id;
 		meb.klass = klass;
 		meb.def = def;