node/test/parallel/test-child-process-fork-regr-gh-2847.js

// Before https://github.com/nodejs/node/pull/2847 a child process trying
// (asynchronously) to use the closed channel to it's creator caused a segfault.
'use strict';

const common = require('../common');
const assert = require('assert');

const cluster = require('cluster');
const net = require('net');

if (!cluster.isMaster) {
  // Exit on first received handle to leave the queue non-empty in master
  process.on('message', function() {
    process.exit(1);
  });
  return;
}

const server = net.createServer(function(s) {
  if (common.isWindows) {
    s.on('error', function(err) {
      // Prevent possible ECONNRESET errors from popping up
      if (err.code !== 'ECONNRESET')
        throw err;
    });
  }
  setTimeout(function() {
    s.destroy();
  }, 100);
}).listen(0, function() {
  const worker = cluster.fork();

  function send(callback) {
    const s = net.connect(server.address().port, function() {
      worker.send({}, s, callback);
    });

    // https://github.com/nodejs/node/issues/3635#issuecomment-157714683
    // ECONNREFUSED or ECONNRESET errors can happen if this connection is still
    // establishing while the server has already closed.
    // EMFILE can happen if the worker __and__ the server had already closed.
    s.on('error', function(err) {
      if ((err.code !== 'ECONNRESET') &&
          (err.code !== 'ECONNREFUSED') &&
          (err.code !== 'EMFILE')) {
        throw err;
      }
    });
  }

  worker.process.once('close', common.mustCall(function() {
    // Otherwise the crash on `channel.fd` access may happen
    assert.strictEqual(worker.process.channel, null);
    server.close();
  }));

  worker.on('online', function() {
    send(function(err) {
      assert.ifError(err);
      send(function(err) {
        // Ignore errors when sending the second handle because the worker
        // may already have exited.
        if (err && err.message !== 'Channel closed') {
          throw err;
        }
      });
    });
  });
});