diff -u b/core/modules/system/system.module b/core/modules/system/system.module
--- b/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -854,7 +854,10 @@
 function system_get_info($type, $name = NULL) {
   $info = array();
   if ($type == 'module') {
-    if (!$data = \Drupal::cache()->get('system.module.data')) {
+    if ($cache = \Drupal::cache()->get('system.module.data')) {
+      $data = $cache->data;
+    }
+    else {
       $data = system_rebuild_module_data();
     }
     foreach (\Drupal::moduleHandler()->getModuleList() as $module => $filename) {