Segmentation faults on 64-bit threaded perl when doing $thread->join

[pdcawley]

We've been experiencing some problems with Kavorka not being thread safe on our 64-bit threaded perl. Eventually we narrowed it down to being a problem with Devel::Pragma, using the following test code:

use strict;
use warnings;
use Test::More;

use Config;
BEGIN {
    plan skip_all => "your perl does not support ithreads"
        unless $Config{useithreads};
};

use threads;

{
    package ThreadedExample;
    use Devel::Pragma;
}

my $subref = sub {
    my $id = shift;
    note("id:$id");
    return $id;
};

my @threads;
my @idents = qw/bar1 bar2 bar3 bar4 bar5 bar6/;
foreach my $foo_id (@idents)
{
    push @threads, threads->create($subref, $foo_id);
}

my @results;
for my $thread (@threads) {
    note("joining thread $thread");
    push @results, $thread->join;
}

is_deeply(
    [ sort @results ],
    [ sort @idents ],
    'expected return values',
);

done_testing;

It doesn't blow up on a 32 bit threaded perl, apparently, and if we roll back to Devel::Pragma 0.54, it's fine too.

[pdcawley]

Further to this, git bisect lays the blame at commit 974553d