php segfaults at zval_delref_p with allow_call_time_pass_reference = Off

Issue

# tail -40 /var/log/httpd/error_log
Fri Jan 04 07:01:35 2013] [notice] child pid 31461 exit signal Segmentation fault (11), possible coredump in /var/www/segfault
[Fri Jan 04 07:01:45 2013] [notice] child pid 31439 exit signal Segmentation fault (11), possible coredump in /var/www/segfault
[Fri Jan 04 07:01:51 2013] [notice] child pid 31458 exit signal Segmentation fault (11), possible coredump in /var/www/segfault
[Fri Jan 04 07:01:58 2013] [notice] child pid 31459 exit signal Segmentation fault (11), possible coredump in /var/www/segfault
[Fri Jan 04 07:02:11 2013] [notice] child pid 31447 exit signal Segmentation fault (11), possible coredump in /var/www/segfault
[Fri Jan 04 07:02:20 2013] [notice] child pid 31648 exit signal Segmentation fault (11), possible coredump in /var/www/segfault
[Fri Jan 04 07:02:36 2013] [notice] child pid 31438 exit signal Segmentation fault (11), possible coredump in /var/www/segfault