diff --git a/ChangeLog b/ChangeLog
index 495934ac8b..e5183f7bf2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Dec 18 21:09:23 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* vm.c (invoke_block): merge 2 stack overflow checks.
+
 Tue Dec 18 20:58:35 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* compile.c, insnhelper.ci, insns.def, object.c, vm.c, vm.h:
diff --git a/vm.c b/vm.c
index 79404a3fa4..29e23b4a6f 100644
--- a/vm.c
+++ b/vm.c
@@ -550,8 +550,7 @@ invoke_block(rb_thread_t *th, rb_block_t *block, VALUE self, int argc, VALUE *ar
 
 	rb_vm_set_finish_env(th);
 
-	CHECK_STACK_OVERFLOW(th->cfp, argc);
-	CHECK_STACK_OVERFLOW(th->cfp, iseq->stack_max);
+	CHECK_STACK_OVERFLOW(th->cfp, argc + iseq->stack_max);
 
 	for (i=0; i<argc; i++) {
 	    th->cfp->sp[i] = argv[i];