diff --git a/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php b/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php
index f49e8cf949..e65b7b331e 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php
@@ -64,8 +64,18 @@ class DecoratorServicePass implements CompilerPassInterface
 
             if (isset($decoratingDefinitions[$inner])) {
                 $decoratingDefinition = $decoratingDefinitions[$inner];
-                $definition->setTags(array_merge($decoratingDefinition->getTags(), $definition->getTags()));
-                $decoratingDefinition->setTags([]);
+
+                $decoratingTags = $decoratingDefinition->getTags();
+                $resetTags = [];
+
+                if (isset($decoratingTags['container.service_locator'])) {
+                    // container.service_locator has special logic and it must not be transferred out to decorators
+                    $resetTags = ['container.service_locator' => $decoratingTags['container.service_locator']];
+                    unset($decoratingTags['container.service_locator']);
+                }
+
+                $definition->setTags(array_merge($decoratingTags, $definition->getTags()));
+                $decoratingDefinition->setTags($resetTags);
                 $decoratingDefinitions[$inner] = $definition;
             }
 
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php
index d8d7587c8d..721426b024 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php
@@ -167,6 +167,25 @@ class DecoratorServicePassTest extends TestCase
         $this->assertEquals(['bar' => ['attr' => 'baz']], $container->getDefinition('deco2')->getTags());
     }
 
+    public function testProcessLeavesServiceLocatorTagOnOriginalDefinition()
+    {
+        $container = new ContainerBuilder();
+        $container
+            ->register('foo')
+            ->setTags(['container.service_locator' => [0 => []], 'bar' => ['attr' => 'baz']])
+        ;
+        $container
+            ->register('baz')
+            ->setTags(['foobar' => ['attr' => 'bar']])
+            ->setDecoratedService('foo')
+        ;
+
+        $this->process($container);
+
+        $this->assertEquals(['container.service_locator' => [0 => []]], $container->getDefinition('baz.inner')->getTags());
+        $this->assertEquals(['bar' => ['attr' => 'baz'], 'foobar' => ['attr' => 'bar']], $container->getDefinition('baz')->getTags());
+    }
+
     protected function process(ContainerBuilder $container)
     {
         $repeatedPass = new DecoratorServicePass();