Recently upgraded two communities to 4.4.2 from 4.3.x and at the same time switched from php 7.0 to 7.3. Every now and then, and it appears to be locked to a "first visit" of the forum, the client is getting a 500 error, and it appears that mysqlnd.so is segfaulting:

nginx log:
2019/04/14 00:20:50 [error] 3747#3747: *390057 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 10.12.13.14, server: forum.myserver.nz, request: "GET / HTTP/1.0", upstream: "fastcgi://unix:/run/php/php7.3-web.sock:", host: "forum.myserver.nz", referrer: "https://myserver.nz/"

php log:
[14-Apr-2019 00:20:50] WARNING: [pool web] child 5334 exited on signal 11 (SIGSEGV - core dumped) after 7377.388536 seconds from star

syslog:
Apr 14 00:20:50 webapp03 kernel: [190397.733992] php-fpm7.3[5334]: segfault at 7f0f1b201018 ip 00007f0f32080de5 sp 00007ffdcf056680 error 4 in mysqlnd.so[7f0f3205f000+36000]

Am running Ubuntu 18.04 using ondrej/php builds, which I use in countless other apps.

uname -a
Linux webapp03 4.15.0-47-generic #50-Ubuntu SMP Wed Mar 13 10:44:52 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.2 LTS
Release:        18.04
Codename:       bionic

apt source
deb http://ppa.launchpad.net/ondrej/php/ubuntu bionic main

Server version: 10.1.38-MariaDB-0ubuntu0.18.04.1 Ubuntu 18.04

 

Anyone else seeing anything like this / have any ideas?

Make sure all your packages are up-to-date first and foremost.

Can you provide us with your exact PHP version and a list of PHP modules you have installed/enabled?

There was an old bug that seems to reference the issue but it should have been fixed early on in the 7.3.x branch,

https://bugs.php.net/bug.php?id=77289

dpkg -l | grep php
ii  php-common                            2:69+ubuntu18.04.1+deb.sury.org+2+php7.3 all          Common files for PHP packages
ii  php-igbinary                          2.0.8-1+ubuntu18.04.1+deb.sury.org+1     amd64        igbinary PHP serializer
ii  php-redis                             4.2.0-1+ubuntu18.04.1+deb.sury.org+1     amd64        PHP extension for interfacing with Redis
ii  php7.3-cli                            7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        command-line interpreter for the PHP scripting language
ii  php7.3-common                         7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        documentation, examples and common module for PHP
ii  php7.3-curl                           7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        CURL module for PHP
ii  php7.3-fpm                            7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        server-side, HTML-embedded scripting language (FPM-CGI binary)
ii  php7.3-gd                             7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        GD module for PHP
ii  php7.3-json                           7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        JSON module for PHP
ii  php7.3-mbstring                       7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        MBSTRING module for PHP
ii  php7.3-mysql                          7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        MySQL module for PHP
ii  php7.3-opcache                        7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        Zend OpCache module for PHP
ii  php7.3-readline                       7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        readline module for PHP
ii  php7.3-xml                            7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        DOM, SimpleXML, WDDX, XML, and XSL module for PHP
ii  php7.3-zip                            7.3.4-1+ubuntu18.04.1+deb.sury.org+3     amd64        Zip module for PHP

 

All packages are generally only ever a week old.

I had these. They went away when I switched to elasticsearch.