Comment 4 for bug 681167

I do agree that the two should conflict, but the segfault is a different issue that may still be a problem with xcache:

(gdb) run
Starting program: /usr/bin/php
[Thread debugging using libthread_db enabled]
PHP Warning: Cannot load module 'XCache' because conflicting module 'apc' is already loaded in Unknown on line 0

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff561de50 in ?? ()
(gdb) bt
#0 0x00007ffff561de50 in ?? ()
#1 0x000000000068fa69 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /build/buildd/php5-5.3.3/Zend/zend.c:1258
#2 0x000000000063ca73 in php_execute_script (primary_file=0x7fffffffdd30) at /build/buildd/php5-5.3.3/main/main.c:2288
#3 0x0000000000729694 in main (argc=-5000, argv=0x0) at /build/buildd/php5-5.3.3/sapi/cli/php_cli.c:1196

Still I think its most likely that PHP or php-apc is handling the error condition poorly since xcache clearly isn't getting loaded.

Interestingly enough, php -i does not segfault, so its only when we try to execute a script.

Marking Confirmed in php5 *and* php-apc. Setting Importance to Low, since there are very few conflicting zend caching modules.