502 Bad Gateway once running php on command line

[marcusy3k]

Eventually I find what went wrong, it should be caused by both Zend OPcache
and XCache are installed, they may conflict each other in this case, once
I've removed the XCache, it works fine, the php command line would no longer
cause the php-fpm error.

XCache should be unnecessary when OPcache is running.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,265576,265584#msg-265584