diff --git a/ChangeLog b/ChangeLog
index 7b8b737e91..53f0269cca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Oct  2 00:42:14 2011  Kazuki Tsujimoto  <kazuki@callcc.net>
+
+	* vm.c (rb_thread_mark): rb_thread_t needs self to be marked.
+	  [ruby-dev:44566] [Bug #5386]
+
 Sat Oct  1 09:48:53 2011  CHIKANAGA Tomoyuki  <nagachika00@gmail.com>
 
 	* gc.c (add_heap_slots, init_heap): reset heaps_inc zero when
diff --git a/vm.c b/vm.c
index 665351be0a..2ab2b92fcc 100644
--- a/vm.c
+++ b/vm.c
@@ -1735,6 +1735,7 @@ rb_thread_mark(void *ptr)
 	RUBY_MARK_UNLESS_NULL(th->first_proc);
 	if (th->first_proc) RUBY_MARK_UNLESS_NULL(th->first_args);
 
+	RUBY_MARK_UNLESS_NULL(th->self);
 	RUBY_MARK_UNLESS_NULL(th->thgroup);
 	RUBY_MARK_UNLESS_NULL(th->value);
 	RUBY_MARK_UNLESS_NULL(th->errinfo);