diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 5cb45c8..ff5d132 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2727,6 +2727,7 @@ function drupal_common_theme() {
     'tablesort_indicator' => array(
       'variables' => array('style' => NULL),
       'template' => 'tablesort-indicator',
+      'preprocess' => array('template_preprocess_tablesort_indicator'),
     ),
     'mark' => array(
       'variables' => array('mark_type' => MARK_NEW),
diff --git a/core/lib/Drupal/Core/Utility/ThemeRegistry.php b/core/lib/Drupal/Core/Utility/ThemeRegistry.php
index a08aa9f..43ce8e0 100644
--- a/core/lib/Drupal/Core/Utility/ThemeRegistry.php
+++ b/core/lib/Drupal/Core/Utility/ThemeRegistry.php
@@ -149,7 +149,7 @@ protected function updateCache($lock = TRUE) {
     }
 
     $lock_name = $this->cid . ':' . __CLASS__;
-    if (!$lock || $this->locks->acquire($lock_name)) {
+    if (!$lock || $this->lock->acquire($lock_name)) {
       if ($cached = $this->cache->get($this->cid)) {
         // Use array merge instead of union so that filled in values in $data
         // overwrite empty values in the current cache.
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 7faf5f1..4dd630f 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -118,7 +118,6 @@ function user_theme() {
     'username' => array(
       'variables' => array('account' => NULL, 'attributes' => array()),
       'preprocess' => array('template_preprocess_username'),
-      'variables' => array('account' => NULL),
     ),
   );
 }