Not receiving core

[scott...@dynamiccatholic.com]

I am trying to debug a SIGSEGV encountered in php-fpm. I think it is occurring the shutdown. I tried generating coredumps while using the user for php-fpm but it would not write them to /tmp/ even with 777 permissions. Coredumps are produced when running php-fpm under the root user (just for testing). However, these coredumps do not have a stack trace. Below are the errors I receive

1. warning: Couldn't find general-purpose registers in core file.
2. #0  0x0000000000000000 in ?? ()

Here is the whole output of gdb: https://pastebin.com/2E29C5G1

How can I have php-fpm generate a working coredump?

Thanks!