Strange memory leak using just threads

[MnkyBrain]

I'm using perl v5.10.0 on a debian lenny system (perl package version 5.10.0-19lenny2) and I'm experiencing a very strange memory leak in a threaded program.

I started stripping down the code to try to find what was causing it (assuming the problem was coming from one of the modules I was using), and was pretty surprised when I got it down to just the threading code, and was still seeing the memory leak. Here's the code:

#! /usr/bin/perl 
use strict;
use warnings;

use threads;
my @child;
my @list = qw(a b c d);

while (1) {
  foreach(@list){
    push(@child,threads->create("test","$_"));
  }

  foreach my $ch (@child) {
    $ch->join();
  }
  @child = ();

}

sub test
{ 
  my ($item) = @_;
}

As you can see, there is absolutely nothing going on other than thread creation/joining, yet this script leaks memory like a sieve on my machine.

Can anyone tell me what I've done wrong?