diff --git a/modules/core/lib/Stats/Output/File.php b/modules/core/lib/Stats/Output/File.php
index 54530065caac4fdb72420221fb22fa8eebd8ad23..be44d70798c7251e064fc692924966f1f4fa0bc2 100644
--- a/modules/core/lib/Stats/Output/File.php
+++ b/modules/core/lib/Stats/Output/File.php
@@ -69,11 +69,11 @@ class File extends \SimpleSAML\Stats\Output
         if ($fh === false) {
             throw new Error\Exception('Error opening log file: '.var_export($fileName, true));
         }
-        $this->file = $fh;
 
         // Disable output buffering
-        stream_set_write_buffer($this->file, 0);
+        stream_set_write_buffer($fh, 0);
 
+        $this->file = $fh;
         $this->fileDate = $date;
     }