Bug 554794 – www-apache/mod_perl causes apache to segfault if used with perl-5.22

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Ladislav Laska 2015-07-13 21:48:03 UTC]

After starting the apache2, it fails early in the module initialization with this stacktrace:

Program received signal SIGSEGV, Segmentation fault.
0x00007fffeceaa47e in modperl_env_init () from /usr/lib64/apache2/modules/mod_perl.so
(gdb) bt
#0  0x00007fffeceaa47e in modperl_env_init () from /usr/lib64/apache2/modules/mod_perl.so
#1  0x00007fffece99c34 in modperl_hook_init () from /usr/lib64/apache2/modules/mod_perl.so
#2  0x0000000000448719 in ap_run_open_logs ()
#3  0x00000000004297a4 in main ()


the problem seem to be that perl-5.22 makes PL_vtbl_env const, and mod_perl tried to write into it. This causes the segfault. More info here:

https://rt.cpan.org/Public/Bug/Display.html?id=101962#txn-1508463

I suggest making mod_perl block perl-5.22, until the problem is resolved.

Reproducible: Always

[Comment 1 Ladislav Laska 2015-07-13 21:57:45 UTC]

This is the commit that causes the problem. Reverting it seem to fix the issue:

http://perl5.git.perl.org/perl.git/commit/c910fead78

[Comment 2 Dan Goodliffe 2015-07-15 11:02:52 UTC]

Confirmed that patching out the referenced commit does stop the segfault.
In my case this allows Apache to run until it hits #550972.

[Comment 3 Timo Gurr (RETIRED) 2015-07-17 08:57:22 UTC]

(Adding URL to the upstream bug report about this issue for reference/tracking of progress.)

[Comment 4 Andreas K. Hüttel 2015-12-10 23:39:28 UTC]

The upstream svn repo at https://svn.apache.org/repos/asf/perl/modperl/trunk has fixes committed, which will be in 2.0.10 (no release date known so far).

[Note that already 2.0.9 claims to work with any apache 2.0-2.4. If we need to stabilize this for Perl 5.22, what do we do with the apache dependency? Make separate stable/nonstable ebuilds for apache 2.2 and apache 2.4???]

[Comment 5 Patrice Clement 2015-12-28 10:36:42 UTC]

Confirmed by our fellow Tobias Klausmann.

[Comment 6 Mark Wagner 2016-01-05 03:17:22 UTC]

Hacked up an svn-trunk-based ebuild at https://github.com/mark-wagner/portage/tree/master/www-apache/mod_perl

Seems to work for me under apache 2.4 and perl 5.22.

[Comment 7 Andreas K. Hüttel 2016-01-05 09:56:57 UTC]

Please try www-apache/mod_perl-2.0.8-r3 (no keywords yet)

[Comment 8 Fernando Cunha 2016-01-08 01:05:07 UTC]

Andreas, 

I can confirm that www-apache/mod_perl-2.0.8-r3  fix the issue. Mod_perl running fine and no more segfaults. 

Thanks

[Comment 9 Andreas K. Hüttel 2016-01-09 19:31:02 UTC]

OK, thanks, keywords restored.