fork BUG?

[Andrew Belashov]

Hello!

Help me to analyse a problem.

Perl crashing in child after fork().

My script working perfectly on FreeBSD 4.7R i386.

---Test session------------------------------------------------
bel at white$ uname -a
FreeBSD white 5.1-RELEASE FreeBSD 5.1-RELEASE #0: Thu Jul 24 11:18:15 
MSD 2003     bel at white:/usr/obj/usr/src/sys/WHITE  sparc64

bel at white$ pkg_version -v|grep ^perl
perl-5.6.1_11                       <   needs updating (port has 5.6.1_13)

bel at white$ perl forkbug.pl
...
Main: sum = 39951.2526718337, cnt = 80000
Parent working...
perl in realloc(): warning: modified (chunk-) pointer
Out of memory!
perl in free(): warning: modified (chunk-) pointer
Parent: sum = 39951.2526718337, cnt = 80000
Parent waiting a child...
Parent exiting...
---End session-------------------------------------------------

With best regards,
  Andrew Belashov.
-------------- next part --------------
#!/usr/bin/perl -w

use IO::Handle;

my %arr;
my @tmpl = ('.', '/', '0'..'9', 'a'..'z', 'A'..'Z');
my $lentmpl = @tmpl;

sub docheck {
 my $prefix = shift;
 my $sum = 0; my $cnt = 0;
 foreach my $key (keys(%arr)) {
  $sum += $arr{$key}; $cnt++;
 }
 print "$prefix: sum = $sum, cnt = $cnt\n";
}

STDOUT->autoflush(1);

for (my $i = 0; $i < 80000; $i++) {
 my $key = '';
 foreach my $j (0..8) {
  $key .= $tmpl[rand($lentmpl)];
 }
 $arr{$key} = rand;
 print "." if (($i % 1000) == 0);
}

print "\n";

&docheck('Main');

die "fork()" unless defined(my $pid = fork());

if ($pid) {
 print "Parent working...\n";
 &docheck('Parent');
 print "Parent waiting a child...\n";
 wait();
 print "Parent exiting...\n";
 exit(0);
} else {
 print "Child working...\n";
 &docheck('Child');
 print "Child exiting...\n";
 exit(0);
}