diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 9fd594a..d7eba77 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -78,14 +78,16 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
    * Holds the list of enabled modules.
    *
    * @var array
-   *   An associative array whose keys are module names and whose values are
-   *   ignored.
+   *   An associative array whose keys are module names and whose values is the
+   *   module weight.
    */
   protected $moduleList;
 
   /**
    * List of available modules and installation profiles.
    *
+   * Its a list of extensions keyed by module name.
+   *
    * @var \Drupal\Core\Extension\Extension[]
    */
   protected $moduleData = array();
@@ -637,10 +639,7 @@ protected function moduleData($module) {
   }
 
   /**
-   * Implements Drupal\Core\DrupalKernelInterface::updateModules().
-   *
-   * @todo Remove obsolete $module_list parameter. Only $module_filenames is
-   *   needed.
+   * {@inheritdoc}
    */
   public function updateModules(array $module_list, array $module_filenames = array()) {
     $this->moduleList = $module_list;
diff --git a/core/lib/Drupal/Core/DrupalKernelInterface.php b/core/lib/Drupal/Core/DrupalKernelInterface.php
index e7c468f..1ec8fa1 100644
--- a/core/lib/Drupal/Core/DrupalKernelInterface.php
+++ b/core/lib/Drupal/Core/DrupalKernelInterface.php
@@ -87,7 +87,7 @@ public function getAppRoot();
    * list.
    *
    * @param array $module_list
-   *   The new list of modules.
+   *   The list of module weights, keyed by module name.
    * @param array $module_filenames
    *   List of module filenames, keyed by module name.
    */
diff --git a/core/lib/Drupal/Core/EventSubscriber/PathRootsSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/PathRootsSubscriber.php
index 8d96767..d7d4b5c 100644
--- a/core/lib/Drupal/Core/EventSubscriber/PathRootsSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/PathRootsSubscriber.php
@@ -26,7 +26,7 @@ class PathRootsSubscriber implements EventSubscriberInterface {
    *
    * @var array
    */
-  protected $pathRoots;
+  protected $pathRoots = [];
 
   /**
    * The state key value store.
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index c6f3921..5632afd 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -188,7 +188,7 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
         drupal_static_reset('system_rebuild_module_data');
 
         // Update the kernel to include it.
-        $this->updateKernel($module_filenames);
+        $this->updateKernel($extension_config->get('module'), $module_filenames);
 
         // Refresh the schema to include it.
         drupal_get_schema(NULL, TRUE);
@@ -403,7 +403,7 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
       \Drupal::service('router.builder_indicator')->setRebuildNeeded();
 
       // Update the kernel to exclude the uninstalled modules.
-      $this->updateKernel($module_filenames);
+      $this->updateKernel($extension_config->get('module'), $module_filenames);
 
       // Update the theme registry to remove the newly uninstalled module.
       drupal_theme_rebuild();
@@ -480,12 +480,12 @@ protected function removeCacheBins($module) {
    * @param string $module_filenames
    *   The list of installed modules.
    */
-  protected function updateKernel($module_filenames) {
+  protected function updateKernel($module_list, $module_filenames) {
     // This reboots the kernel to register the module's bundle and its services
     // in the service container. The $module_filenames argument is taken over as
     // %container.modules% parameter, which is passed to a fresh ModuleHandler
     // instance upon first retrieval.
-    $this->kernel->updateModules($module_filenames, $module_filenames);
+    $this->kernel->updateModules($module_list, $module_filenames);
     // After rebuilding the container we need to update the injected
     // dependencies.
     $container = $this->kernel->getContainer();