diff -u b/core/modules/user/user.pages.inc b/core/modules/user/user.pages.inc
--- b/core/modules/user/user.pages.inc
+++ b/core/modules/user/user.pages.inc
@@ -420,8 +420,7 @@
 function user_page() {
   global $user;
   if ($user->uid) {
-    $request = drupal_container()->get('request');
-    return new RedirectResponse($request->getUriForPath('/user/' . $user->uid));
+    return new RedirectResponse(url('user/' . $user->uid, array('absolute' => TRUE)));
   }
   else {
     return drupal_get_form('user_login');
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/UpgradePathTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/UpgradePathTestBase.php
@@ -10,6 +10,7 @@ namespace Drupal\system\Tests\Upgrade;
 use Drupal\Core\Database\Database;
 use Drupal\simpletest\WebTestBase;
 use Exception;
+use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 
 /**
  * Perform end-to-end tests of the upgrade path.
@@ -251,8 +252,14 @@ abstract class UpgradePathTestBase extends WebTestBase {
     module_implements_reset();
 
     // Rebuild caches.
+    // @todo Remove the try/catch when UpgradePathTestBase::setup() is fixed to
+    //   boot DrupalKernel (as WebTestBase::setup() does).
     drupal_static_reset();
-    drupal_flush_all_caches();
+    try {
+      drupal_flush_all_caches();
+    }
+    catch (InvalidArgumentException $e) {
+    }
 
     // Reload global $conf array and permissions.
     $this->refreshVariables();
--- a/core/update.php
+++ b/core/update.php
@@ -16,6 +16,7 @@
 
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\DependencyInjection\Reference;
 
 // Change the directory to the Drupal root.
 chdir('..');
@@ -445,6 +446,17 @@ update_fix_d8_requirements();
 drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
 drupal_maintenance_theme();
 
+// @todo Remove after converting update.php to use DrupalKernel.
+$container = drupal_container();
+$container->register('database', 'Drupal\Core\Database\Connection')
+  ->setFactoryClass('Drupal\Core\Database\Database')
+  ->setFactoryMethod('getConnection')
+  ->addArgument('default');
+$container->register('router.dumper', '\Drupal\Core\Routing\MatcherDumper')
+  ->addArgument(new Reference('database'));
+$container->register('router.builder', 'Drupal\Core\Routing\RouteBuilder')
+  ->addArgument(new Reference('router.dumper'));
+
 // Turn error reporting back on. From now on, only fatal errors (which are
 // not passed through the error handler) will cause a message to be printed.
 ini_set('display_errors', TRUE);