diff --git a/src/Symfony/Component/HttpKernel/Kernel.php b/src/Symfony/Component/HttpKernel/Kernel.php
index e7e3282d49db7..10e943ca0f845 100644
--- a/src/Symfony/Component/HttpKernel/Kernel.php
+++ b/src/Symfony/Component/HttpKernel/Kernel.php
@@ -467,7 +467,7 @@ protected function initializeContainer()
         try {
             is_dir($buildDir) ?: mkdir($buildDir, 0777, true);
 
-            if ($lock = fopen($cachePath.'.lock', 'w')) {
+            if ($lock = fopen($cachePath.'.lock', 'w+')) {
                 if (!flock($lock, \LOCK_EX | \LOCK_NB, $wouldBlock) && !flock($lock, $wouldBlock ? \LOCK_SH : \LOCK_EX)) {
                     fclose($lock);
                     $lock = null;