log4perl-devel

[log4perl-devel] Log4Perl Segmentation Faults with Apache1/mod_perl

[H. M. <log...@sb...>]

Hi,

I've just encountered very frequent segmentation faults when trying to
use Log4Perl in a perl web application running inside of apache 1.3.37
and mod_perl 1.29. I am using perl 5.8.8 and the latest Log4Perl version
from CPAN.

Have any problems with such a setup been reported before? (I wasn't able
to find anything in the bug tracker or the mailing list archive)

Greetings
H. Meyer

Re: [log4perl-devel] Log4Perl Segmentation Faults with Apache1/mod_perl

[Mike S. <m...@pe...>]

On Mon, 6 Aug 2007, H. Meyer wrote:

> I've just encountered very frequent segmentation faults when trying to
> use Log4Perl in a perl web application running inside of apache 1.3.37
> and mod_perl 1.29. I am using perl 5.8.8 and the latest Log4Perl
> version from CPAN.

Core dumps are unrelated to CPAN modules using plain Perl like Log4perl.

If a core dump happens, the Perl interpreter perl crashes, which it
shouldn't do if plain Perl is used (and not compiled .xs code).

Can you verify where the problem happens? I've recently written an
article that shows how to track this down:

    http://www.linux-magazin.de/heft_abo/ausgaben/2007/01/getriebeschaden

(In German only, English version still embargoed).

-- Mike

Mike Schilli
m...@pe...

>
> Have any problems with such a setup been reported before? (I wasn't able
> to find anything in the bug tracker or the mailing list archive)
>
> Greetings
> H. Meyer
>
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Re: [log4perl-devel] Log4Perl Segmentation Faults with Apache1/mod_perl

[H. M. <log...@sb...>]

Mike Schilli wrote:
> On Mon, 6 Aug 2007, H. Meyer wrote:
>> I've just encountered very frequent segmentation faults when trying to
>> use Log4Perl in a perl web application running inside of apache 1.3.37
>> and mod_perl 1.29. I am using perl 5.8.8 and the latest Log4Perl
>> version from CPAN.
> 
> Core dumps are unrelated to CPAN modules using plain Perl like Log4perl.
> 
> If a core dump happens, the Perl interpreter perl crashes, which it
> shouldn't do if plain Perl is used (and not compiled .xs code).

We've been able to "fix" the issue for our local setup.
The following appender caused the segfaults:

log4perl.appender.STDERR=Log::Dispatch::Screen
log4perl.appender.STDERR.stderr=1
log4perl.appender.STDERR.layout=Log::Log4perl::Layout::PatternLayout
log4perl.appender.STDERR.layout.ConversionPattern=%d %-5p %5P %6X{uid}
%c:%M{1}:%L - %m%n

Corresponding apache error log entries:

DIED: Can't locate object method "DESTROY" via package
"Log::Dispatch::Screen" at
/usr/local/share/perl/5.8.8/Log/Log4perl/Logger.pm line 73.
[Mon Aug  6 11:29:18 2007] [notice] child pid 21957 exit signal
Segmentation fault (11)

Once that appender is disabled, everything (we currently only use
Log::Dispatch::File) works without problems.

Greetings
H. Meyer

Re: [log4perl-devel] Log4Perl Segmentation Faults with Apache1/mod_perl

[Mike S. <m...@pe...>]

On Tue, 7 Aug 2007, H. Meyer wrote:

> We've been able to "fix" the issue for our local setup.  The following
> appender caused the segfaults:
>
> log4perl.appender.STDERR=Log::Dispatch::Screen
> log4perl.appender.STDERR.stderr=1
> log4perl.appender.STDERR.layout=Log::Log4perl::Layout::PatternLayout
> log4perl.appender.STDERR.layout.ConversionPattern=%d %-5p %5P %6X{uid}
> %c:%M{1}:%L - %m%n

Nothing wrong with this appender. Just for kicks you might want to try
the screen appender that comes with Log4perl,
Log::Log4perl::Appender::Screen, but it shouldn't make a difference. It
supports the same parameters.

Are you using any other libraries with Apache? It is very common that
one bad library causes problems leading to crashes in another, innocent,
library (mod_perl in your case).

 -- Mike

Mike Schilli
m...@pe...

> Corresponding apache error log entries:
>
> DIED: Can't locate object method "DESTROY" via package
> "Log::Dispatch::Screen" at
> /usr/local/share/perl/5.8.8/Log/Log4perl/Logger.pm line 73.
> [Mon Aug  6 11:29:18 2007] [notice] child pid 21957 exit signal
> Segmentation fault (11)
>
> Once that appender is disabled, everything (we currently only use
> Log::Dispatch::File) works without problems.
>
> Greetings
> H. Meyer
>
> -------------------------------------------------------------------------
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> Still grepping through log files to find problems?  Stop.
> Now Search log events and configuration files using AJAX and a browser.
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> _______________________________________________
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>