Server.getConnections() failed with "Slave closed before reply" #13923

'use strict';
var cluster = require('cluster');
var net = require('net');
if (cluster.isMaster) {
    console.log('Nodejs version :', process.version);
    var cpuCount = require('os').cpus().length;
    var workers = [];

    var spawn = function(workerIndex) {
        var worker = cluster.fork();
        workers[workerIndex] = worker;
        worker.on('exit', function() {
            spawn(workerIndex);
        });
    };
    for (var i = 0; i < cpuCount; i++) spawn(i);

    var masterHttpServer = net.createServer({ pauseOnConnect: true }, function(socket) {
        //var worker = workers[Number('0' + socket.remoteAddress.replace(/[abcdef:.]/g, '')) % cpuCount];
        var worker = workers[0];
        worker.send('xxx-http-session:connection', socket);
    }).listen(12345);

    setInterval(function() {
        //XXX: will return errors if some worker dies with unclosed socket
        masterHttpServer.getConnections(function(err, counts) {
            if (!err) console.info('active connections : ' + counts);
            else console.info('errors ocurred when getConnections ：' + err);
        });
    }, 1000);

    setInterval(function() {
       workers[0].kill();
    }, 1000);

} else {
    var server = require('http').createServer(function(req, res) {
        res.end('Anythings returns to the browser! ');
    });

    process.on('message', function(message, socket) {
        if (message !== 'xxx-http-session:connection') return;
        server.emit('connection', socket);
        socket.resume();
    });
}

process.on('uncaughtException', function(err) {
    console.log('uncaughtException:', err.stack);
});
process.on('exit', function(code) {
    console.warn('process is down ! exit code :', code);
});