diff --git a/ChangeLog b/ChangeLog
index d4d6af1da2..faeccaef17 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Aug 19 06:03:27 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_insnhelper.c (vm_push_frame): initialize block_iseq.  a patch
+	  from Peter Weldon at [ruby-core:31757].
+
 Wed Aug 18 19:08:17 2010  Kenta Murata  <mrkn@mrkn.jp>
 
 	* array.c (ary_make_shared): revert r29037, it occurs SEGV some
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 2e01703f7c..985a2fb5a8 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -58,6 +58,7 @@ vm_push_frame(rb_thread_t * th, const rb_iseq_t * iseq,
     cfp->self = self;
     cfp->lfp = lfp;
     cfp->dfp = sp;
+    cfp->block_iseq = 0;
     cfp->proc = 0;
     cfp->me = 0;