Dear monks,

I'm searching your help while trying to overcome an issue with a script using Net::Curl::Multi in an Amazon Linux 2023 instance.

At first run, I hit the wall and get a trace like

$ ./04-curl-multi-debug.pl 
TRACE 1
TRACE 2
TRACE 3
TRACE 4
GET_ONE 1 
GET_ONE 2 
GET_ONE 3 $$self: 1
GET_ONE 4 
GET_ONE 6 
GET_ONE 3 $$self: 1
GET_ONE 4 
callback function is not set
Operation was aborted by an application callbackTRACE 6: 'Operation wa
+s aborted by an application callback'
[download]

Subsequent runs will do their job OK - for a short while. Then again a "callback function is not set"... And then again a number of runs will do OK. The script I've tried to track down the issue is here:

#!/usr/bin/perl

package Multi::Simple;

use strict;
use warnings;
use Net::Curl::Multi;
use base qw(Net::Curl::Multi);

# make new object, preset the data
sub new
{
        my $class = shift;
        my $active = 0;
        return $class->SUPER::new( \$active );
}

# add one handle and count it
sub add_handle($$)
{
        my $self = shift;
        my $easy = shift;

        $$self++;
        $self->SUPER::add_handle( $easy );
}

# perform until some handle finishes, does all the magic needed
# to make it efficient (check as soon as there is some data)
# without overusing the cpu.
sub get_one($)
{
        my $self = shift;
print "GET_ONE 1 \n";
        if ( my @result = $self->info_read() ) {
                $self->remove_handle( $result[ 1 ] );
                return @result;
        }

print "GET_ONE 2 \n";
        while ( $$self ) {
print "GET_ONE 3 \$\$self: $$self\n";
                my $t = $self->timeout;
                if ( $t != 0 ) {
                        $t = 10000 if $t < 0;
                        my ( $r, $w, $e ) = $self->fdset;

                        select $r, $w, $e, $t / 1000;
                }

print "GET_ONE 4 \n";
                my $ret = $self->perform();
                if ( $$self != $ret ) {
                        $$self = $ret;
                        if ( my @result = $self->info_read() ) {
                                $self->remove_handle( $result[ 1 ] );
                                return @result;
                        }
print "GET_ONE 5 \n";
                }
print "GET_ONE 6 \n";
        };
print "GET_ONE 7 \n";

        return ();
}

1;

###############################################
###############################################
###############################################

package main;
#use strict;
use warnings;

BEGIN {
    push @INC, './';
}

use Data::Dumper;
#use Multi::Simple;
use Net::Curl qw(:constants);
use Net::Curl::Easy  qw(:constants);
use Net::Curl::Multi qw(:constants);
use Net::Curl::Share qw(:constants);

#print "libcurl version: ", Net::Curl::version(), "\n";
#            my $vi = Net::Curl::version_info();
#            unless ( $vi->{features} & CURL_VERSION_SSL ) {
#                die "SSL support is required\n";
#            }
#print "Version Info: ", Dumper( $vi );

#use Net::Curl;

#my $info = Net::Curl::version_info();
#print "libcurl version: $info->{version}\n";
#print "ares_num: $info->{ares_num}\n";
#print "features: $info->{features}\n";

#exit;

sub easy
{
        my $uri = shift;
        my $share = shift;

        #require Net::Curl::Easy qw(:constants);

        my $easy = Net::Curl::Easy->new( { uri => $uri, body => '' } )
+;
        $easy->reset;
        $easy->setopt( Net::Curl::Easy::CURLOPT_VERBOSE(), 1 );
        $easy->setopt( Net::Curl::Easy::CURLOPT_SSL_SESSIONID_CACHE, 0
+ );
        $easy->setopt( Net::Curl::Easy::CURLOPT_DNS_USE_GLOBAL_CACHE, 
+0);
        $easy->setopt( Net::Curl::Easy::CURLOPT_URL(), $uri );
        $easy->setopt( Net::Curl::Easy::CURLOPT_WRITEHEADER(),
                \$easy->{headers} );
        $easy->setopt( Net::Curl::Easy::CURLOPT_FILE(),
                \$easy->{body} );
        #$easy->setopt( Net::Curl::Easy::CURLOPT_SHARE(), $share );

        # This wasn't needed prior to curl 7.67, which changed the int
+erface
        # so that an easy that uses a cookie-share now requires an exp
+licit
        # cookie-engine enable to use cookies. Previously the easy's u
+se of
        # a cookie-share implicitly enabled the easy's cookie engine.
        #$easy->setopt( Net::Curl::Easy::CURLOPT_COOKIEFILE(), q<> );

        return $easy;
}

my $multi;
eval {
    $multi = Multi::Simple->new();
    print "TRACE 1\n";

    my $dummy = Net::Curl::Easy->new;
    $dummy->setopt(Net::Curl::Easy::CURLOPT_URL, 'http://example.com')
+;
    #$dummy->setopt(Net::Curl::Easy::CURLOPT_WRITEFUNCTION, sub { retu
+rn length($_[0]); });
    if (not ref $dummy) {
        die "Cannot create easy object...?!\n";
    }
    print "TRACE 2\n";
    $multi->add_handle( $dummy );
    print "TRACE 3\n";
    $multi->wait(10000);
    print "TRACE 4\n";

    my @results = $multi->get_one();

    if (scalar( @results ) == 0) {
        die "Some ERROR occured in get_one!\n";
    }

    my ($msg, $easy, $result) = @results;
    print "TRACE 5 Msg: ", Dumper( $msg ), "easy: ", Dumper( $easy ), 
+"Result: " , Dumper( $result );
    #Net::Curl::Easy::strerror( $result ), "\n";
    if ($result != Net::Curl::Easy::CURLE_OK) {
        my $message = Net::Curl::Easy::strerror( $result );
        print "Result as string: '$message'\n";
    }

};
if ($@) {
    print "TRACE 6: '$@'";
    die $@;
}

print "NO ERROR, all OK\n";
exit;
[download]

The code runs fine on an older Amazon Linux 2 instance. Any idea on how a work-around might look like? Thank you!