RedHat 7.2
The parameter pcre.recursion_limit is set to 100000 by default. If recursion eats more memory than the system stack size can provide (commonly 8 MB),
PHP will error out on complex regular expressions showing a Segmentation fault error message.

Solution:

Create a new /etc/systemd/system/.d/ directory
For example:

mkdir /etc/systemd/system/httpd.service.d

Create a new /etc/systemd/system/.d/.conf drop-in config file with the desired setting in the appropriate context type
For example:

echo [Service] >/etc/systemd/system/httpd.service.d/ulimit.conf
echo LimitSTACK=infinity >>/etc/systemd/system/httpd.service.d/ulimit.conf

Execute systemctl daemon-reload

systemctl daemon-reload

Execute systemctl restart

systemctl restart httpd