diff --git a/core/lib/Drupal/Core/DependencyInjection/Compiler/StackedKernelPass.php b/core/lib/Drupal/Core/DependencyInjection/Compiler/StackedKernelPass.php
index 86f08a1..845867a 100644
--- a/core/lib/Drupal/Core/DependencyInjection/Compiler/StackedKernelPass.php
+++ b/core/lib/Drupal/Core/DependencyInjection/Compiler/StackedKernelPass.php
@@ -9,7 +9,6 @@
 
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
 
 /**
@@ -28,6 +27,13 @@ public function process(ContainerBuilder $container) {
       return;
     }
 
+    $stacked_kernel = $container->getDefinition('http_kernel');
+
+    // Return now if this is not a stacked kernel.
+    if ($stacked_kernel->getClass() !== 'Stack\StackedHttpKernel') {
+      return;
+    }
+
     $middlewares = [];
     $priorities = [];
 
@@ -38,22 +44,20 @@ public function process(ContainerBuilder $container) {
 
     array_multisort($priorities, SORT_ASC, $middlewares);
 
-    $inner_id = 'http_kernel.basic';
-    $middlewares_param = [new Reference($inner_id)];
+    $decorated_id = 'http_kernel.basic';
+    $middlewares_param = [new Reference($decorated_id)];
     foreach ($middlewares as $id => $decorator) {
       // Prepend a reference to the middlewares container parameter.
       array_unshift($middlewares_param, new Reference($id));
 
       // Prepend the inner kernel as first constructor argument.
       $arguments = $decorator->getArguments();
-      array_unshift($arguments, new Reference($inner_id));
+      array_unshift($arguments, new Reference($decorated_id));
       $decorator->setArguments($arguments);
 
-      $inner_id = $id;
-      $http_kernel = $decorator;
+      $decorated_id = $id;
     }
 
-    $stacked_kernel = $container->getDefinition('http_kernel');
     $arguments = [$middlewares_param[0], $middlewares_param];
     $stacked_kernel->setArguments($arguments);
   }
diff --git a/core/tests/Drupal/Tests/Core/DependencyInjection/Compiler/StackedKernelPassTest.php b/core/tests/Drupal/Tests/Core/DependencyInjection/Compiler/StackedKernelPassTest.php
new file mode 100644
index 0000000..654d9a8
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/DependencyInjection/Compiler/StackedKernelPassTest.php
@@ -0,0 +1,116 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\DependencyInjection\Compiler\StackedKernelPassTest.
+ */
+
+namespace Drupal\Tests\Core\DependencyInjection\Compiler;
+
+use Drupal\Core\DependencyInjection\Compiler\StackedKernelPass;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Component\DependencyInjection\Definition;
+
+/**
+ * @coversDefaultClass \Drupal\Core\DependencyInjection\Compiler\StackedKernelPass
+ */
+class StackedKernelPassTest extends UnitTestCase {
+
+  /**
+   * The stacked kernel pass.
+   *
+   * @var \Drupal\Core\DependencyInjection\Compiler\StackedKernelPass
+   */
+  protected $stackedKernelPass;
+
+  /**
+   * @var \Drupal\Core\DependencyInjection\Container
+   */
+  protected $containerBuilder;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    $this->stackedKernelPass = new StackedKernelPass();
+    $this->containerBuilder = new ContainerBuilder();
+  }
+
+  /**
+   * @covers ::process
+   */
+  public function testProcessWithStackedKernel() {
+    $stacked_kernel = new Definition('Stack\StackedHttpKernel');
+
+    $this->containerBuilder->setDefinition('http_kernel', $stacked_kernel);
+    $this->containerBuilder->setDefinition('http_kernel.basic', $this->createMiddlewareServiceDefinition(FALSE, 0));
+
+    $this->containerBuilder->setDefinition('http_kernel.three', $this->createMiddlewareServiceDefinition());
+    $this->containerBuilder->setDefinition('http_kernel.one', $this->createMiddlewareServiceDefinition(TRUE, 10));
+    $this->containerBuilder->setDefinition('http_kernel.two', $this->createMiddlewareServiceDefinition(TRUE, 5));
+
+    $this->stackedKernelPass->process($this->containerBuilder);
+
+    $stacked_kernel_args = $this->containerBuilder->getDefinition('http_kernel')->getArguments();
+
+    // Check the stacked kernel args.
+    $this->assertSame((string) $stacked_kernel_args[0], 'http_kernel.one');
+    $this->assertCount(4, $stacked_kernel_args[1]);
+    $this->assertSame((string) $stacked_kernel_args[1][0], 'http_kernel.one');
+    $this->assertSame((string) $stacked_kernel_args[1][1], 'http_kernel.two');
+    $this->assertSame((string) $stacked_kernel_args[1][2], 'http_kernel.three');
+    $this->assertSame((string) $stacked_kernel_args[1][3], 'http_kernel.basic');
+
+    // Check the modified definitions.
+    $definition = $this->containerBuilder->getDefinition('http_kernel.one');
+    $args = $definition->getArguments();
+    $this->assertSame('http_kernel.two', (string) $args[0]);
+    $this->assertSame('test', $args[1]);
+
+    $definition = $this->containerBuilder->getDefinition('http_kernel.two');
+    $args = $definition->getArguments();
+    $this->assertSame('http_kernel.three', (string) $args[0]);
+    $this->assertSame('test', $args[1]);
+
+    $definition = $this->containerBuilder->getDefinition('http_kernel.three');
+    $args = $definition->getArguments();
+    $this->assertSame('http_kernel.basic', (string) $args[0]);
+    $this->assertSame('test', $args[1]);
+  }
+
+  /**
+   * @covers ::process
+   */
+  public function testProcessWithHttpKernel() {
+    $kernel = new Definition('Symfony\Component\HttpKernel\HttpKernelInterface');
+    $this->containerBuilder->setDefinition('http_kernel', $kernel);
+    $this->stackedKernelPass->process($this->containerBuilder);
+
+    $unprocessed_kernel = $this->containerBuilder->getDefinition('http_kernel');
+
+    $this->assertSame($kernel, $unprocessed_kernel);
+    $this->assertSame($kernel->getArguments(), $unprocessed_kernel->getArguments());
+  }
+
+  /**
+   * Creates a middleware definition.
+   *
+   * @param bool $tag
+   *   Whether ot not to set the http_middleware tag.
+   * @param int $priority
+   *   The priority to be used for the tag.
+   *
+   * @return \Symfony\Component\DependencyInjection\Definition
+   */
+  protected function createMiddlewareServiceDefinition($tag = TRUE, $priority = 0) {
+    $definition = new Definition('Symfony\Component\HttpKernel\HttpKernelInterface', ['test']);
+
+    if ($tag) {
+      $definition->addTag('http_middleware', ['priority' => $priority]);
+    }
+
+    return $definition;
+  }
+
+}