net: ignore UV_EALREADY in tryReadStart

lib/net.js

@@ -62,6 +62,7 @@ const {
 const assert = require('internal/assert');
 const {
   UV_EADDRINUSE,
+  UV_EALREADY,
   UV_EBADF,
   UV_EINVAL,
   UV_ENOTCONN,
@@ -928,7 +929,7 @@ function tryReadStart(socket) {
   debug('Socket._handle.readStart');
   socket._handle.reading = true;
   const err = socket._handle.readStart();
-  if (err)
+  if (err && err !== UV_EALREADY)
     socket.destroy(new ErrnoException(err, 'read'));
 }
 

test/parallel/test-net-read-start-ealready.js

@@ -0,0 +1,41 @@
+// Flags: --expose-internals
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const net = require('net');
+const { internalBinding } = require('internal/test/binding');
+const { UV_EALREADY } = internalBinding('uv');
+
+// Close the server from the accepted connection rather than from the client's
+// 'close'. Closing the listening handle can race ahead of the accept callback
+// and drop the pending connection, so 'connection' would never fire.
+const server = net.createServer(common.mustCall((connection) => {
+  connection.on('error', common.mustNotCall());
+  connection.resume();
+  connection.on('close', common.mustCall(() => server.close()));
+}));
+
+server.listen(0, '127.0.0.1', common.mustCall(() => {
+  const socket = net.createConnection({
+    host: '127.0.0.1',
+    port: server.address().port,
+  });
+
+  socket.on('connect', common.mustCall(() => {
+    const readStart = socket._handle.readStart;
+    socket._handle.readStart = () => UV_EALREADY;
+    socket._handle.reading = false;
+
+    socket._read(0);
+
+    assert.strictEqual(socket.destroyed, false);
+    assert.notStrictEqual(socket._handle, null);
+
+    socket._handle.readStart = readStart;
+    socket.destroy();
+  }));
+
+  socket.on('error', common.mustNotCall());
+  socket.on('close', common.mustCall());
+}));