diff --git a/ChangeLog b/ChangeLog
index 62e7708f48..5a819e873c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Dec 15 11:53:36 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* thread.c (rb_thread_wait_fd_rw): remove silly rb_thread_alone()
+	  check.
+
 Sat Dec 15 10:22:38 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread.c (rb_thread_polling): revert but deprecate.
diff --git a/thread.c b/thread.c
index 4ea4c58f5d..190125a296 100644
--- a/thread.c
+++ b/thread.c
@@ -3320,7 +3320,6 @@ rb_thread_wait_fd_rw(int fd, int read)
     if (fd < 0) {
 	rb_raise(rb_eIOError, "closed stream");
     }
-    if (rb_thread_alone()) return;
     while (result <= 0) {
 	result = rb_wait_for_single_fd(fd, events, NULL);