mod_perl causing Apache Segmentation fault - why?

Question

My mod_perl appears to cause a segmentation fault in my Apache. 'httpd -X' simply gives 'Segmentation Fault' and my server does not start.

I am using Apache 2.2.22, mod_perl 2.0.5, CentOS 5.7 x86_64. I built mod_perl and Apache together from source with the following command:

perl5.12.4 Makefile.PL MP_USE_STATIC=1 MP_AP_PREFIX=/usr/local/src/httpd-2.2.22 MP_AP_CONFIGURE="--with-mpm=prefork --enable-rewrite"

What I have tried so far:

1. Point httpd.conf to my Catalyst application. Result: Apache dies with 'Segmentation fault'.
2. Point httpd.conf to a simple application created with catalyst.pl. Apache dies with 'Segmentation fault'.
3. Point httpd.conf to a static site. Result: Apache starts fine and serves the website.

I tried the following:

gdb -c /usr/local/apache2/bin/httpd

Program received signal SIGSEGV, Segmentation fault.

0x00002aaab0db0270 in ?? ()

(gdb) bt

#0 0x00002aaab0db0270 in ?? ()

#1 0x00000000004c9d24 in Perl_newUNOP ()

#2 0x00000000004fb6a6 in Perl_yyparse ()

#3 0x0000000000557c57 in S_doeval ()

#4 0x0000000000559546 in Perl_pp_require ()

#5 0x0000000000528bae in Perl_runops_standard ()

#6 0x00000000004d5d2f in Perl_eval_sv ()

#7 0x0000000000478425 in modperl_require_module ()

#8 0x0000000000472283 in modperl_boot ()

#9 0x00000000005529cc in Perl_leave_scope ()

#10 0x00000000004d87eb in S_parse_body ()

#11 0x00000000004d927c in perl_parse ()

#12 0x0000000000471d2a in modperl_startup ()

#13 0x0000000000471cbc in modperl_startup ()

#14 0x000000000047202e in modperl_init ()

#15 0x000000000047215f in modperl_hook_init ()

#16 0x00000000004737bb in modperl_cmd_perldo ()

#17 0x000000000046432b in invoke_cmd (cmd=0x5b9880, parms=0x7fffffffe770, mconfig=0x844728, args=0x89b7d8 "use lib qw( /usr/local/apache2/virtualhosts/api.nwwi.nl /httpdocs/lib/ );\\n") at config.c:757

#18 0x0000000000465865 in ap_walk_config_sub (current=0x89b828, parms=0x7fffffffe770, section_vector=0x830c18) at config.c:1163

#19 0x0000000000465914 in ap_walk_config (current=0x89b828, parms=0x7fffffffe770, section_vector=0x830c18) at config.c:1196

#20 0x0000000000466cb9 in ap_process_config_tree (s=0x82de10, conftree=0x86fcb0, p=0x822138, ptemp=0x82a178) at config.c:1765

#21 0x0000000000449512 in main (argc=2, argv=0x7fffffffe9e8) at main.c:723

I have no idea how to read and interpret this. Can somebody help and point me in a direction to further troubleshoot this?

Answer 1

I received the following response from Dave Hodgkinson on the mod_perl mailing list:

#17 0x000000000046432b in invoke_cmd (cmd=0x5b9880,

 parms=0x7fffffffe770, mconfig=0x844728, args=0x89b7d8 "use lib qw( 

/usr/local/apache2/virtualhosts/api.nwwi.nl /httpdocs/lib/ );\\n") at

 config.c:757 

This appears to be what it's trying to do. Take that directive out and see what happens?

After some experimentation I changed part of the Apache configuration from

PerlSwitches -I/srv/www/example.com/application/lib/

<Perl>
    use lib qw( /srv/www/example.com/application/lib/ );
</Perl>

PerlModule application

to

<Perl>
    use lib qw( /srv/www/example.com/application/lib/ );
</Perl>

and this fixed my issue.