Did you get somethig like

[Tue Jan  7 17:18:00 2003] [notice] child pid 7460 exit signal Segmentation fault (11)
[Tue Jan  7 17:18:01 2003] [notice] child pid 7466 exit signal Segmentation fault (11)

in your apache+mod_perl errorlog and you do not have a clue where it is happening?

Try the follwing GDB procedure:

% gdb httpd
(gdb) source mod_perl-x.xx/.gdbinit
(gdb) run -X
[make a request that core dumps]
(gdb) curinfo

should print the Perl filename:linenumber

i.e. mod_perl-x.xx/.gdbinit debugging info which allows you to nicely display where the crash actually happened

see also http://archive.davintech.ca/modperl/2000-08/msg00575.phtml

Alberto