I am using Net::SSH2 module to make ssh connections to remote machines. I am trying to invoke these ssh connections as threads, and am getting the below errors :

Attempt to free non-existent shared string 'io_socket_type', Perl inte
+rpreter: 0x84972e0 during global destruction.
Attempt to free non-existent shared string 'io_socket_proto', Perl int
+erpreter: 0x84972e0 during global destruction.
Attempt to free non-existent shared string 'io_socket_domain', Perl in
+terpreter: 0x84972e0 during global destruction.
Attempt to free non-existent shared string 'io_socket_timeout', Perl i
+nterpreter: 0x84972e0 during global destruction.
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Package code:

package sshConnector;

sub new {
    my $class = shift;
    my $deviceInfo = shift;
    my $self = {};
    my $ssh2;

    my ($ip,$port,$username,$password) = @$deviceInfo;

    # Invoke an ssh connection to the device
    eval {
         $ssh2 = Net::SSH2->new();
         $ssh2->connect($ip,$port) or die 
    };
    if ($@) {
         print "Failed to make connection $@\n";
         return 1;
    }

    # Send credentials for authentication
    my $res;
    if ($res = $ssh2->auth_keyboard($username, $password)) {
        $self->{'HANDLE'} = $ssh2;
    }
    return $self;
}

sub cmd {
    my $self = shift;
    my $cmd = shift;
    my $bufLength = 10000;

    my $connHandle = $sshHandle->channel();

    # Make the connection blocking - wait until cmd exits
    $connHandle->blocking(1);

    # Merge the stderr contents also into the stdout buffer
    $connHandle->ext_data('merge');

    # Execute the command
    eval {
        $connHandle->exec($cmd);
    };
    if ($@) {
        print "Failed to execute cmd\n";
        return 1;
    }

    # Initialize the buffer with all 0s
    $buf = '0' x $bufLength;

    # Read the buffer if anything is present in the output
    $connHandle->read($buf,$bufLength)) {
    $output = $buf;

    $exitStatus = $connHandle->exit_status();
    print "output is $output, exit status is $exitStatus\n";

    $connHandle->exec('exit');
    $connHandle->close;
    return ($exitStatus,$output);
}
1;
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Script:

use sshConnector;

my $machine1 = new Connector($deviceInfo1);

my $machine2 = new Connector($deviceInfo2);

sub methodA {
    my $self = shift;
    my $count = shift;
    my $hostname;

    while ($count) {
        ($status,$hostname) = $self->cmd("hostname");
        print "$count : $hostname\n";
        sleep 1;
        $count--;
    }
}

sub methodB {
    my $self = shift;
    my $count = shift;
    my $hostname;

    while ($count) {
        ($status,$hostname) = $self->cmd("hostname");
        print "$count : $hostname\n";
        sleep 2;
        $count--;
    }
}

my $thr1 = threads->create('methodA',$machine1,10);
my $thr2 = threads->create('methodB',$machine2,6);

$thr1->join();
print "First thread over\n";

$thr2->join();
print "Second thread over\n";
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The threads started and continued till end, but the script exits before printing the last two print statements. Can someone please help? Why am I getting this error? Net-SSH2 is a threadsafe module, as far as I know. Am I missing something?