AW: print throwing intermittent Segfaults

Hi Willian,

Thanks for your checklist, I've run through it, segfaults still there...
Right now it takes less then a minute from apache restart to the first segfault.
This is from the error_log from the RedHat 5 Production machine:

Apache2::RequestIO::print: (103) Software caused connection abort at 

The guys from rackspace are saying that I should recompile all my perl modules installed directly from CPAN ( see above ) , do you think this would help?
Or has someone another hint?

Thanks

Denis

-----Ursprüngliche Nachricht-----
Von: William T [mailto:[email protected]] 
Gesendet: Samstag, 21. November 2009 19:28
An: Denis Banovic
Cc: [email protected]
Betreff: Re: print throwing intermittent Segfaults

This is the list of stuff I usually start with when I get a problem that doesn't seem to be tied to a particular code path.

  * code path - perhaps a particular code path is only being exercised rarely, and it has a bug
  * forking - when child dies, all open descriptors in it's name space also get closed
  * eval - always a good thing to look at when weird things happen
  * persistancy - globals, closures, persistant objects, serialized/restored objects, shared memory, shared objects (between
processes)

-wjt


--------------------------------------------------------------------------------
Von: Denis Banovic [mailto:[email protected]] 
Gesendet: Samstag, 21. November 2009 10:43
An: [email protected]
Betreff: print throwing intermittent Segfaults


Hi Everybody,

I'm having big problems with mod_perl throwing intermittent Segmentation faults our production machines on RHEL 4 & 5.
To be able to produce a core dump on this segfaults I've installed mod_dumpcore from this tutorial:
http://mituzas.lt/2009/09/26/getting-apache-core-dumps-in-linux/

gdb /usr/sbin/httpd core.1 produces following output:

#0  0x00b29f4b in XS_Apache__RequestRec_content_type ()  from /usr/lib/perl5/vendor_perl/5.8.5/i386-linux-thread-multi/auto/Apache/RequestRec/RequestRec.so

and very rarely ( 1 in 15 )

#0  0x003830b9 in apr_palloc () from /usr/lib/libapr-0.so.0


The content-type is set by
$r->content_type("text/html; charset=iso-8859-1") but this is not what is causing him to segfault...

By try and error I've figured out that the segfault happens when I do a
$r->print($mypagecontent);

I've even tried to do a
unless($r->connection->aborted) {
    $r->print($mypagecontent);
}
 but this didn't help either.

The segfault happens randomly, between 30 and 250 mod_perl requests. There is no specific request URL or script that causes him to segfault, it just happens after some time.
More load on the server means more segfaults. 

From my Apache Config:
<IfModule prefork.c>
StartServers       8
MinSpareServers    5
MaxSpareServers   20
ServerLimit      256
MaxClients       200
MaxRequestsPerChild  15
</IfModule>

There are some additional Perl Modules that I've build from CPAN:
Compress-Zlib-2.004
Digest-MD5-2.39
Email-MIME-1.861
Email-MIME-ContentType-1.014
Email-MIME-Encodings-1.311
Email-Simple-2.004
Encode-Detect-1.01
ExtUtils-CBuilder-0.23
File-Slurp-9999.12
IO-Compress-Zlib-2.004
MIME-Base64-3.07
MIME-Types-1.24
Module-Build-0.2808
Pod-Escapes-1.04
Pod-Simple-3.07
String-Similarity-1.03
Template-Plugin-XML-Escape-0.02
Test-Pod-1.26
Test-Simple-0.80

Has anyone a hint where to start looking and what to do next to figure out why this segfault is happening?

Thanks

Denis