Php – Enabling fast cgi on php 5.3.29

The error code -1073741571 (0xc00000fd) means Stack Overflow. You will need to debug your code.

I think your max_children is too low

<value name="max_children">3</value>

Also you can try switching from TCP port to unix socket for php-fpm:

php-fpm.conf

<value name="listen_address">/tmp/php.sock</value>

nginx.conf

fastcgi_pass unix:/tmp/php.sock;

Elaborated:

1. Unix sockets are ~20% faster
2. You don't use time-wait sockets for each connect