From mongodb/mongo-php-driver#213:

i use swoole (https://github.com/swoole/swoole-src) , mongodb together, test code like

<?php

$server = new swoole_server('127.0.0.1', 9501);
$server->set(array(
    'worker_num' => 1,
    'task_worker_num' => 2,
    'log_file'   => './swoole.log'
));

$server->on('workerStart', function($serv, $worker_id){
    echo 'worker start :' . $worker_id . ',pid :' . getmypid() . PHP_EOL;
});

$server->on('task', function($serv, $task_id, int $from_id, string $data){
    echo 'on task  :' . $task_id . ',pid :' . getmypid() . PHP_EOL;
});

$server->on('finish', function($serv, $task_id, string $data){
    echo 'on finish  :' . $task_id . ',pid :' . getmypid() . PHP_EOL;
});

$server->on('receive', function ($serv, $fd, $from_id, $data) {
    $serv->reload(true);
});

$server->start();

where server receive any data, i will set server to reload, but occurs

[Mon Feb  1 17:12:39 2016]  Script:  '/Users/xingqiba/Desktop/haha.php'
---------------------------------------
/Users/xingqiba/data/softs/mongodb-1.1.2/php_phongo.c(2248) : Block 0x7fe95255a040 status:
Beginning:  	Freed (magic=0x00000000, expected=0x99954317)
    Start:	Overflown (magic=0x00000035 instead of 0x4060D864)
          	At least 4 bytes overflown
worker start :1,pid :71250
[Mon Feb  1 17:12:39 2016]  Script:  '/Users/xingqiba/Desktop/haha.php'
---------------------------------------
/Users/xingqiba/data/softs/mongodb-1.1.2/php_phongo.c(2248) : Block 0x7fe95255a040 status:
Beginning:  	Freed (magic=0x00000000, expected=0x99954317)
    Start:	Overflown (magic=0x00000035 instead of 0x4060D864)
          	At least 4 bytes overflown

if i don't use mongodb in php.ini, it's ok!