diff --git a/lib/private/cache/fileglobalgc.php b/lib/private/cache/fileglobalgc.php
index c95154952de4ed281032e4d36cda4c0a7a29b40e..63de24fa50b521f8ed5e402d599c13bd9a504139 100644
--- a/lib/private/cache/fileglobalgc.php
+++ b/lib/private/cache/fileglobalgc.php
@@ -66,6 +66,7 @@ class FileGlobalGC extends Job {
 		if (!is_dir($cacheDir)) {
 			return;
 		}
-		array_walk($this->getExpiredPaths($cacheDir, $now), 'unlink');
+		$paths = $this->getExpiredPaths($cacheDir, $now);
+		array_walk($paths, 'unlink');
 	}
 }