Segmentation fault when enable PDO::ATTR_PERSISTENT

[razonyang]

If you know how to write phpt tests, please open a PR with environment information, and your test, this will cause CI to test your issue before a human is able to look

Environment

$ php72 -v
PHP 7.2.12 (cli) (built: Nov 29 2018 14:57:26) ( ZTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies

$ php72 -dextension=pthreads.so --ri pthreads | grep Version
PHP Warning:  Module 'pthreads' already loaded in Unknown on line 0
Version => 3.1.7dev

OS: Linux, Deepin

• PHP: can be obtained with php -v
• pthreads: can be obtained with php -dextension=pthreads.so --ri pthreads | grep Version
• OS: if Windows, include arch

Summary

A summary isn't always necessary, code > words ... delete this section, as applicable.

Reproducing Code

<?php

$threads = [];
$threadsCount = 2;

for ($i = 0; $i < $threadsCount; $i++) {
    $thread = new MyThread();
    $threads[] = $thread;
    $thread->start();
}

foreach ($threads as $thread) {
    $thread->join();
}

class MyThread extends \Thread
{
    public function run()
    {
        for ($j = 0; $j < 3; $j++) {
            $conn = new PDO('mysql:host=127.0.0.1', 'root', '', [
                PDO::ATTR_PERSISTENT => true,
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            ]);
        }
    }
}

Bug reports must come with reproducing code, please ensure code is formatted correctly.

If the code cannot be a single script, please link to a gist, or a github repository containing the reproducing code.

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Please ensure code is self contained, and executable: if the code cannot be executed, the bug cannot be reproduced.

Expected Output

Please include the expected output, properly formatted.

Actual Output

Segmentation fault

Please include the actual output, properly formatted.

[sirsnyder]

This is related to PDO and not yet fixable in pthreads. I can only recommend to avoid persistent connections.