PHP 8.2 FPM Leaks processes on pcntl_fork

Comienza con el reproductor index.php de Drupal 10 proporcionado, especialmente la llamada a pcntl_fork() y el comportamiento de los procesos de PHP-FPM. Reprodúcelo con PHP 8.2.10 en Ubuntu 16.04 y compáralo con PHP 7.4. Se considera terminado cuando los procesos bifurcados se limpian después de la espera, en lugar de separarse y permanecer bajo el proceso maestro de FPM.

Description

OS: xenial
PHP tested: 8.2.7, 8.2.10

The following drupal 10 index.php:

<?php

/**
 * @file
 * The PHP page that serves all page requests on a Drupal installation.
 *
 * All Drupal code is released under the GNU General Public License.
 * See COPYRIGHT.txt and LICENSE.txt files in the "core" directory.
 */

use Drupal\Core\DrupalKernel;
use Symfony\Component\HttpFoundation\Request;

$autoloader = require_once 'autoload.php';

$kernel = new DrupalKernel('prod', $autoloader);

$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();
$pid = pcntl_fork();
    if ( $pid !== 0  ) {
        // we are the parent process
        return;
    }
    sleep(10);

$kernel->terminate($request, $response);

After doing ~5 requests to the site, results in the following sub-processes to the FPM master:

root     15873  0.0  0.8 464188 17200 ?        Ss   13:08   0:00 php-fpm: master process (/var/www/site-fpm/drush12test.prod/php-fpm-8.2.conf)
drush12+ 16518  0.7  1.4 466300 29860 ?        S    13:11   0:00  \_ php-fpm: pool drush12test
drush12+ 16557  0.0  0.6 466300 13068 ?        S    13:11   0:00      \_ php-fpm: pool drush12test
drush12+ 16559  0.0  0.6 466300 12640 ?        S    13:11   0:00      \_ php-fpm: pool drush12test
drush12+ 16561  0.0  0.6 466300 12640 ?        S    13:11   0:00      \_ php-fpm: pool drush12test
drush12+ 16563  0.0  0.6 466300 12640 ?        S    13:11   0:00      \_ php-fpm: pool drush12test

But then after a few seconds, when it should clean them up, they will instead detach and linger around:

root     15873  0.0  0.8 464188 17188 ?        Ss   13:08   0:00 php-fpm: master process (/var/www/site-fpm/drush12test.prod/php-fpm-8.2.conf)
drush12+ 16557  0.0  1.1 464252 23364 ?        S    13:11   0:00 php-fpm: pool drush12test
drush12+ 16559  0.0  1.1 464252 23028 ?        S    13:11   0:00 php-fpm: pool drush12test
drush12+ 16561  0.0  1.1 464252 23028 ?        S    13:11   0:00 php-fpm: pool drush12test
drush12+ 16563  0.0  1.1 466300 23432 ?        S    13:11   0:00 php-fpm: pool drush12test

The same doesn't happen with PHP 7.4. In that case the processes get cleaned up properly.

PHP Version

PHP 8.2.10

Operating System

Ubuntu 16.04