diff --git a/ChangeLog b/ChangeLog
index 00461603c9..6d2afcffea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Wed Mar 24 23:43:40 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* thread.c (thread_create_core): let new thread inherit RUBY_EVENT_VM
+	  of event_flags.  [ruby-core:25191]
+
+	* thread.c (rb_threadptr_exec_event_hooks): delete RUBY_EVENT_VM if
+	  all event_hooks are removed.
+
 Wed Mar 24 22:58:02 2010  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* configure.in: revert the previous commit, which seemed to break make
diff --git a/thread.c b/thread.c
index c56f3b72dc..a3dfe007b2 100644
--- a/thread.c
+++ b/thread.c
@@ -549,6 +549,9 @@ thread_create_core(VALUE thval, VALUE args, VALUE (*fn)(ANYARGS))
     th->thgroup = GET_THREAD()->thgroup;
 
     native_mutex_initialize(&th->interrupt_lock);
+    if (GET_VM()->event_hooks != NULL)
+	th->event_flags |= RUBY_EVENT_VM;
+
     /* kick thread */
     st_insert(th->vm->living_threads, thval, (st_data_t) th->thread_id);
     err = native_thread_create(th);
@@ -3769,7 +3772,12 @@ rb_threadptr_exec_event_hooks(rb_thread_t *th, rb_event_flag_t flag, VALUE self,
 	exec_event_hooks(th->event_hooks, flag, self, id, klass);
     }
     if (wait_event & RUBY_EVENT_VM) {
-	exec_event_hooks(th->vm->event_hooks, flag, self, id, klass);
+	if (th->vm->event_hooks == NULL) {
+	    th->event_flags &= (~RUBY_EVENT_VM);
+	}
+	else {
+	    exec_event_hooks(th->vm->event_hooks, flag, self, id, klass);
+	}
     }
     th->errinfo = errinfo;
 }