diff --git a/ChangeLog b/ChangeLog
index f2ef0e2216..6fb575a9a3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jul 19 14:18:22 2012  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* ext/socket/init.c (rsock_init_sock): need to update max fd on all
+	  platforms.
+
 Thu Jul 19 14:15:48 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread.c (rb_gc_mark_threads): remove deprecated function.
diff --git a/ext/socket/init.c b/ext/socket/init.c
index 990f1a4d6b..696b62d82a 100644
--- a/ext/socket/init.c
+++ b/ext/socket/init.c
@@ -52,6 +52,7 @@ rsock_init_sock(VALUE sock, int fd)
     if (!S_ISSOCK(sbuf.st_mode))
         rb_raise(rb_eArgError, "not a socket file descriptor");
 #else
+    rb_update_max_fd(fd);
     if (!rb_w32_is_socket(fd))
         rb_raise(rb_eArgError, "not a socket file descriptor");
 #endif