comment on

Note: See also bug #83364 (RESOLVED) filed towards perl core.

I have a perl daemon that in principle (unless stopped or restarted) will run forever. From time to time it crashes inexplicably after having emitted errors like shown below:

Variable "$self" will not stay shared at (eval 999973501) line 15.
Variable "$self" will not stay shared at (eval 999975201) line 15.
Global symbol "$i" requires explicit package name at (eval 999977609) 
+line 42.
[download]

I notice the eval counter (if such a thing exists) in each case seems to be very close to 10**9. Is there a hard coded limit somewhere in the perl interpreter that might explain this behavior, or should I look in the mirror for root causes?

Update 1: Similar symptoms previously described here.

Update 2: I manage to reproduce the problem using a slightly altered verison of code from this node (thanks Jeppe). Note that the problem only manifests after running almost 4 hours on my Intel(R) Core(TM)2 Quad CPU Q9450 @2.66GHz, (perl v5.10.0, x86_64-linux, Linux 2.6.18) :

use strict;
use warnings;

use Inline C => q{ int evalseq() { return PL_evalseq; }};
use Log::Log4perl;
use Log::Dispatch::FileRotate;

my $conf = q(
  log4perl.category.Script          = DEBUG, ScriptFileRotateAppender
  log4perl.appender.ScriptFileRotateAppender           = Log::Dispatch
+::FileRotate
  log4perl.appender.ScriptFileRotateAppender.filename  = evalseq.log
  log4perl.appender.ScriptFileRotateAppender.mode      = append
  log4perl.appender.ScriptFileRotateAppender.size      = 10000000
  log4perl.appender.ScriptFileRotateAppender.max       = 50
  log4perl.appender.ScriptFileRotateAppender.layout    = PatternLayout
  log4perl.appender.ScriptFileRotateAppender.layout.ConversionPattern=
+[%p] %d %m%n
);

Log::Log4perl::init( \$conf );
my $log = Log::Log4perl::->get_logger(q(Script));

my $count = 0;

until ($@) {
  $count++;
  eval 'my $abc = 1; $abc++; ';
  unless ($count % 1e5) {
    $log->info( "count=$count  evalseq=" . evalseq() );
  }
}

$log->error( $count .' ' .$@ );

__END__

$ perl -v
This is perl, v5.10.0 built for x86_64-linux
$ uname -a
Linux desktop 2.6.18-194.8.1.el5 #1 SMP Thu Jul 1 19:04:48 EDT 2010 x8
+6_64 x86_64 x86_64 GNU/Linux
[download]

The output:

[INFO] 2011/01/31 10:03:54 count=100000  evalseq=100026
[INFO] 2011/01/31 10:03:55 count=200000  evalseq=200027
[INFO] 2011/01/31 10:03:56 count=300000  evalseq=300028
[INFO] 2011/01/31 10:03:58 count=400000  evalseq=400029
[INFO] 2011/01/31 10:03:59 count=500000  evalseq=500030
...
[INFO] 2011/01/31 13:45:23 count=1073300000  evalseq=1073310758
[INFO] 2011/01/31 13:45:24 count=1073400000  evalseq=1073410759
[INFO] 2011/01/31 13:45:26 count=1073500000  evalseq=1073510760
[INFO] 2011/01/31 13:45:27 count=1073600000  evalseq=1073610761
[INFO] 2011/01/31 13:45:28 count=1073700000  evalseq=1073710762
[ERROR] 2011/01/31 13:45:29 1073733744 Global symbol "$abc" requires e
+xplicit package name at (eval 1073744507) line 1.
[download]

Update 3: Reproduced in 7 hours with perl v5.10.1 MSWin32-x86-multi-thread:

use strict;
use warnings;

use Log::Log4perl;

my $conf = q(
  log4perl.category.Script          = DEBUG, ScriptFileRotateAppender,
+ Screen
  log4perl.appender.ScriptFileRotateAppender           = Log::Log4perl
+::Appender::File

  log4perl.appender.ScriptFileRotateAppender.filename  = evalseq.log
  log4perl.appender.ScriptFileRotateAppender.mode      = append
  log4perl.appender.ScriptFileRotateAppender.size      = 10000000
  log4perl.appender.ScriptFileRotateAppender.max       = 50
  log4perl.appender.ScriptFileRotateAppender.layout    = PatternLayout
  log4perl.appender.ScriptFileRotateAppender.layout.ConversionPattern=
+[%p] %d %m%n

  log4perl.appender.Screen         = Log::Log4perl::Appender::Screen
  log4perl.appender.Screen.stderr  = 0
  log4perl.appender.Screen.layout    = PatternLayout
  log4perl.appender.Screen.layout.ConversionPattern=[%p] %d %m%n

);

Log::Log4perl::init( \$conf );
my $log = Log::Log4perl::->get_logger(q(Script));

my $count = 0;

until ($@) {
  $count++;
  eval 'my $abc = 1; $abc++; ';
  unless ($count % 1e5) {
    $log->info( "count=$count" );
  }
}

$log->error( "count=$count " .$@ );

__END__
[download]

Output:

[INFO] 2011/02/01 13:53:09 count=100000
[INFO] 2011/02/01 13:55:12 count=100000
[INFO] 2011/02/01 13:55:14 count=200000
...
[INFO] 2011/02/01 20:49:06 count=1073500000
[INFO] 2011/02/01 20:49:08 count=1073600000
[INFO] 2011/02/01 20:49:11 count=1073700000
[ERROR] 2011/02/01 20:49:12 count=1073740465 Global symbol "$abc" requ
+ires explicit package name at (eval 1073740483) line 1.
[download]

--
No matter how great and destructive your problems may seem now, remember, you've probably only seen the tip of them. [1]

In reply to Interpreter eval counter out of bounds by andreas1234567

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


Clear questions and runnable code get the best and fastest answer
	PerlMonks