PHP: php.unit.so segfault with limits.requests>0

[hanikesn]

When benchmarking my symfony application running in a unit docker container I encountered the following segfault after increasing limits.requests to 1000:

FROM --platform=linux/amd64 unit:1.30.0-php8.2

RUN apt-get update && apt-get -y install libicu-dev \
    && docker-php-ext-install intl \
    && docker-php-ext-install pdo_mysql \
    && echo "zend_extension=opcache.so" > /usr/local/etc/php/conf.d/ext-opcache.ini

"memory_limit": "128M",
"opcache.jit_buffer_size": "128M",
"opcache.max_accelerated_files": "20000",
"opcache.memory_consumption": "256",
"opcache.preload":  "/app/config/preload.php",
"opcache.preload_user": "unit",
"opcache.validate_timestamps": "0",
"realpath_cache_size": "4096K",
"realpath_cache_ttl": "600"

unitd: segfault at 78 ip 00007fbe074a7efd sp 00007ffdb6b70ec0 error 4 in php.unit.so[7fbe074a3000+c000]
[9283731.859396] Code: 8d 15 7f 79 00 00 be 02 00 00 00 e8 bd f4 ff ff b8 01 00 00 00 5d c3 66 0f 1f 44 00 00 41 55 41 54 55 48 89 fd 53 48 83 ec 18 <83> 7f 78 02 77 7d 8d 04 d2 41 89 f4 89 d3 44 8d 6c 41 18 48 8b 47

I'm still working on reproducing this issue/getting a proper core dump as:

ERROR: apport (pid 1464528) Sun Jun 18 18:04:23 2023: executable was modified after program start, ignoring

[ac000]

@hanikesn

HI, thanks for the report.

Couple of questions

1. Can you confirm the version of Unit you're using?.
2. Is this 100% reproducible?

Also, could you provide your unit config (or at least as much as you're comfortable with).

[ac000]

Couple of questions

1. Can you confirm the version of Unit you're using?.

OK, nevermind, I see unit:1.30.0-php8.2

2. Is this 100% reproducible?

I'm guessing not, due to your comment about trying to get coredumps...

I've tried reproducing with the following config on Fedora 38 with latest Unit from git master and PHP 8.2.7

{
    "listeners": {
        "[::1]:8080": {
            "pass": "applications/php"
        }
    },

    "applications": {
        "php": {
            "type": "php",
            "root": "/home/andrew/src/php",
            "processes": 5,
            "limits": {
                "requests": 1000
            },
            "options": {
                "file": "/etc/php.ini",
                "admin": {
                    "memory_limit": "128M",
                    "opcache.jit_buffer_size": "128M",
                    "opcache.max_accelerated_files": "20000",
                    "opcache.memory_consumption": "256",
                    "opcache.preload":  "/home/andrew/src/php/index.php",
                    "opcache.preload_user": "unit",
                    "opcache.validate_timestamps": "0",
                    "realpath_cache_size": "4096K",
                    "realpath_cache_ttl": "600"
                }
            }
        }
    }
}

$ ab -c 20 -n 100000 http://localhost:8080/index.php

and where index.php is simply

<?php

echo "OK\n\n";
print_r($_SERVER);

?>

But no joy yet...