diff --git a/src/Symfony/Component/Process/Pipes/UnixPipes.php b/src/Symfony/Component/Process/Pipes/UnixPipes.php
index 2bf669733e09..46130302dabf 100644
--- a/src/Symfony/Component/Process/Pipes/UnixPipes.php
+++ b/src/Symfony/Component/Process/Pipes/UnixPipes.php
@@ -120,7 +120,7 @@ public function readAndWrite($blocking, $close = false)
             do {
                 $data = fread($pipe, self::CHUNK_SIZE);
                 $read[$type] .= $data;
-            } while (isset($data[0]));
+            } while (isset($data[0]) && ($close || isset($data[self::CHUNK_SIZE - 1])));
 
             if (!isset($read[$type][0])) {
                 unset($read[$type]);