When you try to access the contents of a specific memory address, the only thing that can happen is a segmentation fault. I experimented with this:

#!/usr/bin/perl

BEGIN {
    $|  = 1;
    $^W = 1;
}

use strict;
use autodie;
use warnings FATAL => 'syntax';
use Data::Dumper::Concise;

use POSIX;
use POSIX::RT::Signal qw/sigwaitinfo sigqueue/;
use threads;

use Scalar::Util qw/refaddr/;
use Devel::Pointer::PP;

POSIX::sigprocmask( POSIX::SIG_BLOCK, POSIX::SigSet->new(&POSIX::SIGRT
+MIN) );
my $thr = threads->create( \&_thread );

sub _thread {
    my $sigset = POSIX::SigSet->new(&POSIX::SIGRTMIN);
    my $info   = sigwaitinfo($sigset);
}

my $address = 5;
refaddr( \$address );

my $new_address = \$address;
$$new_address = $$new_address * 4;
sigqueue( $$, &POSIX::SIGRTMIN, $address );
$thr->join();
print Dumper($address);

my $smash = unsmash_sv( 0 + $address ); 
print Dumper($smash);

exit(0);
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