After updating Apache httpd on a server running FreeBSD, it went offline at exactly midnight the following night, producing a log entry like this in httpd-errors:

[Tue Aug 10 00:00:01 2010] [notice] SIGHUP received. Attempting to restart
[Tue Aug 10 00:00:01 2010] [notice] seg fault or similar nasty error detected in the parent process

The server would start right back up using an "apachectl start" command and everything seemed to work fine unless httpd was told to restart or restart gracefully ("apachectl graceful") and then it will crash.

In this case we had newsyslog(8) under FreeBSD rotating Apache httpd's log files at midnight. After it moves the files it then tells the server to restart so it established new file handles. This restart command was triggering the seg fault and ensuing crash.

After much testing, I deduced that it was a conflict between httpd itself and the PHP module "mhash.so". In this situation I was able to simply uninstall and disable it from the extensions.ini file as it was actually not needed.