FWIW, this doesn't crash.

#!/usr/bin/perl

use 5.10.1;
use strict;
use warnings;
use IO::Socket::INET;
use Time::Piece;
use Time::HiRes ('sleep');
use DBI;
use AutoLoader qw(AUTOLOAD);
use POSIX qw(:signal_h);
use threads 
    ('stack_size' => 64*4096,
     'exit' => 'threads_only',
     'stringify');
               
my $shost    = '192.168.0.201';
my $sport    = 60004;
my $mhost    = '192.168.0.201';
my $dbname   = 'enterprise';
my $dbuser   = 'root';
my $dbpasswd = '123456';

sub send_message {
    my $message = shift @_;
    die 'Connect failed!'
      unless my $sock = 'IO::Socket::INET'
          ->new( 'PeerAddr', $shost, 'PeerPort', $sport, 'Proto', 'tcp
+' );
    print $sock $message;
}

sub get_message {
    my $dbh = 'DBI'->connect( "DBI:mysql:database=$dbname;host=$mhost"
+,
        $dbuser, $dbpasswd, { 'PrintError', 0, 'RaiseError', 1 } );
    my $sth = $dbh->prepare('SELECT IMEI FROM SessionIMEI');
    $sth->execute;
    my @elements;
    while ( my $ref = $sth->fetchrow_hashref ) {
        push @elements, $$ref{'IMEI'};
    }
    my $buf = '$0';
    foreach my $ref (@elements) {
        $buf .= ",$ref";
    }
    $buf .= "\@\r\n";
    $dbh->disconnect;
    return $buf;
}
my $sigset = POSIX::SigSet->new(SIGINT);
my $signal = undef;
$sigset->delset(\&POSIX::SIGUSR1);
$sigset->delset(\&POSIX::SIGINT);
$sigset->delset(\&POSIX::SIGALRM);
my $old_sigset = POSIX::SigSet->new;

sub user_handler {
    print "Get a user defined signal.\n";
    $signal = shift @_;
}

sub int_handler {
    print "Get a interrupt signal.\n";
    $signal = shift @_;
    print $signal, "\n";
}

sub alarm_handler {
    print "Get a alarm signal.\n";
    $signal = shift @_;
}
$SIG{'USR1'} = \&user_handler;
$SIG{'INT'}  = \&int_handler;
$SIG{'ALRM'} = \&alarm_handler;
unless ( defined sigprocmask( \&SIG_BLOCK, $sigset, $old_sigset ) ) {
     warn "could not block sigint\n"
    }
    else {
     print "blocked sigint\n";  
}

sub sig_process {
    sigsuspend($sigset);
    my $message = undef;
    if ( $signal eq 'INT' ) {
        $message = get_message();
        send_message $message;
    }
}

sub create_alarm {
    sub start_thread {
        my @args = @_;
        say "Thread started: ", 
        join(' ', @args);
    } 
    my $thr = 'threads'->create('start_thread', \&alarm_thread);
    $thr->detach();
    if($thr->is_detached) {
        print "Thread is detached\n";
    }
    else {
        print "Thread is not detached\n";
    }
    
}

sub alarm_thread {
    eval {
        local $SIG{'ALRM'} = sub { die "alarm\n"; };
        alarm 10;
        my $buffer;
        my $nread = sysread SOCKET, $buffer, 1;
        close SOCKET;
        alarm 0;
        };
        if ($@) {
            die unless $@ eq "alarm\n";
        }
        else {
            return;
        }
}
create_alarm;
sig_process;
[download]

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