Description:
------------
if php.ini set:
disable_functions = exec, 
and enable opcache

php-cgi run:
<?php
function_exists('exec');
?>

will output: Segmentation fault (core dumped)

but this is OK:
<?php
function_exists('exec111111');
?>

Test script:
---------------
<?php
// if php.ini set  disable_functions = exec, and enable opcache
// will output: Segmentation fault (core dumped)
function_exists('exec');

echo "test1";
?>

Expected result:
----------------
test1

Actual result:
--------------
error output:
Segmentation fault (core dumped)

dmesg:
php-cgi[30749]: segfault at 8c ip 00007f255e03c360 sp 00007ffff85b6610 error 4 in opcache.so[7f255e020000+22000]
php-cgi[30839]: segfault at 8c ip 00007f971496a360 sp 00007fff1318ca90 error 4 in opcache.so[7f971494e000+22000]
php-cgi[30959]: segfault at 8c ip 00007f0169148360 sp 00007fff8904ad30 error 4 in opcache.so[7f016912c000+22000]
php-cgi[31106]: segfault at 8c ip 00007f86644e5360 sp 00007fff1a5142a0 error 4 in opcache.so[7f86644c9000+22000]
php-cgi[31162]: segfault at 8c ip 00007eff90f7c360 sp 00007fff03e3eca0 error 4 in opcache.so[7eff90f60000+22000]
php-cgi[31341]: segfault at 8c ip 00007fc47c1e7360 sp 00007ffffb720a00 error 4 in opcache.so[7fc47c1cb000+22000]