PHP 8.2 FPM Leaks processes on pcntl_fork

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

Bắt đầu với reproducer index.php Drupal 10 được cung cấp, đặc biệt là lệnh gọi pcntl_fork() và hành vi của các tiến trình PHP-FPM. Tái hiện vấn đề này với PHP 8.2.10 trên Ubuntu 16.04 và so sánh với PHP 7.4. Hoàn thành khi các tiến trình được fork được dọn dẹp sau sleep thay vì tách ra và tiếp tục tồn tại dưới tiến trình master của FPM.