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child_process: guard against race condition
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It is possible that the internal hnadleMessage() might try to send to
a channel that has been closed. The result can be an AssertionError.
Guard against this.

Fixes: #4205
PR-URL: #4418
Reviewed-By: Brian White <[email protected]>
Reviewed-By: Johan Bergström <[email protected]>
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Trott committed Dec 27, 2015
1 parent 082cc8d commit 57a51a0
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3 changes: 3 additions & 0 deletions lib/internal/child_process.js
Original file line number Diff line number Diff line change
Expand Up @@ -675,6 +675,9 @@ function setupChannel(target, channel) {

const INTERNAL_PREFIX = 'NODE_';
function handleMessage(target, message, handle) {
if (!target._channel)
return;

var eventName = 'message';
if (message !== null &&
typeof message === 'object' &&
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33 changes: 33 additions & 0 deletions test/parallel/test-cluster-disconnect-race.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,33 @@
'use strict';

// This code triggers an AssertionError on Linux in Node.js 5.3.0 and earlier.
// Ref: https://github.com/nodejs/node/issues/4205

const common = require('../common');
const assert = require('assert');
const net = require('net');
const cluster = require('cluster');
cluster.schedulingPolicy = cluster.SCHED_NONE;

if (cluster.isMaster) {
var worker1, worker2;

worker1 = cluster.fork();
worker1.on('message', common.mustCall(function() {
worker2 = cluster.fork();
worker1.disconnect();
worker2.on('online', common.mustCall(worker2.disconnect));
}));

cluster.on('exit', function(worker, code) {
assert.strictEqual(code, 0, 'worker exited with error');
});

return;
}

var server = net.createServer();

server.listen(common.PORT, function() {
process.send('listening');
});

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