diff --git a/hphp/system/php.txt b/hphp/system/php.txt
index 54747df5e..eba3755a8 100644
--- a/hphp/system/php.txt
+++ b/hphp/system/php.txt
@@ -45,6 +45,7 @@ hphp/system/php/lang/ErrorException.php
 hphp/system/php/lang/Serializeable.php
 hphp/system/php/pdo/PDOException.php
 hphp/system/php/reflection/reflection.php
+hphp/system/php/sessions/session_register_shutdown.php
 hphp/system/php/soap/SoapFault.php
 hphp/system/php/spl/datastructures/SplObjectStorage.php
 hphp/system/php/spl/datastructures/SplPriorityQueue.php
diff --git a/hphp/system/php/sessions/session_register_shutdown.php b/hphp/system/php/sessions/session_register_shutdown.php
new file mode 100644
index 000000000..a92f66efa
--- /dev/null
+++ b/hphp/system/php/sessions/session_register_shutdown.php
@@ -0,0 +1,5 @@
+<?php
+
+function session_register_shutdown() {
+  register_shutdown_function('session_write_close');
+}