perl segfault if script not found

[faxm0dem]

syslog-ng segfaults when it can't find the script for the perl module.
The ERRNO is hidden as it gets spit on STDERR.

See syslog-ng/syslog-ng/issues/221

[talien]

Hi!

I have a quick'n'dirty fix for this in my repo (talien/syslog-ng-incubator), on branch f/perl-fixes.
Could you please verify, that this patch solves your use-case? Can you test this patch in threaded(yes) environment? I think I should rethink the unholy marriage of our perl destination and syslog-ng multithreaded model.

[faxm0dem]

unfortunately, your branch causes syslog-ng to segfault every time.
When using master, I get 50% segfaults on startup, and sometimes I get perl errors from init function which seem to indicate a race condition. I suspect something not being enforced in the right order.
Here's the stack trace from your branch:

Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/usr/local/sbin/syslog-ng -Fv'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007ff27009cc73 in ?? () from /usr/lib/x86_64-linux-gnu/perl5/5.20/auto/Sub/Name/Name.so
(gdb) bt full
#0  0x00007ff27009cc73 in ?? () from /usr/lib/x86_64-linux-gnu/perl5/5.20/auto/Sub/Name/Name.so
No symbol table info available.
#1  0x00007ff271e9dcfb in Perl_pp_entersub () from /usr/lib/x86_64-linux-gnu/libperl.so.5.20
No symbol table info available.
#2  0x00007ff271e965b6 in Perl_av_iter_p () from /usr/lib/x86_64-linux-gnu/libperl.so.5.20
No symbol table info available.
#3  0x000000000255f400 in ?? ()
No symbol table info available.
#4  0x0000000002a05490 in ?? ()
No symbol table info available.
#5  0x00000000025b8440 in ?? ()
No symbol table info available.
#6  0x0000000000000000 in ?? ()
No symbol table info available.

[talien]

Hi!

That's bad news. Can you get me the most simple config, on which you can reproduce the segfault?

[juhaszviktor]

Hi!

Sorry, but I can't reproduce this segfault at my machine.
Can you share your config and the core file of syslog-ng?
And of course description of the steps causes the segfault will be welcome :)
It would be a great help for us.

Thanks,
Viktor

[faxm0dem]

did you run the test on @talien's branch or on master?

[juhaszviktor]

I tried it on master.

[faxm0dem]

I cannot reproduce with master and a minimal config. Thanks for looking into this