diff --git a/src/Util/PHP/DefaultPhpProcess.php b/src/Util/PHP/DefaultPhpProcess.php
index b85e31048e2..16568274c4d 100644
--- a/src/Util/PHP/DefaultPhpProcess.php
+++ b/src/Util/PHP/DefaultPhpProcess.php
@@ -16,11 +16,13 @@
 use function is_array;
 use function is_resource;
 use function proc_close;
+use function proc_get_status;
 use function proc_open;
 use function rewind;
 use function stream_get_contents;
 use function sys_get_temp_dir;
 use function tempnam;
+use function time_nanosleep;
 use function unlink;
 use PHPUnit\Framework\Exception;
 
@@ -119,6 +121,10 @@ protected function runProcess(string $job, array $settings): array
 
         fclose($pipes[0]);
 
+        while (proc_get_status($process)['running'] === true) {
+            time_nanosleep(0, 100000);
+        }
+
         $stderr = $stdout = '';
 
         if (isset($pipes[1])) {