worker: fix crash when SharedArrayBuffer outlives creating thread

Keep a reference to the `ArrayBuffer::Allocator` alive for at least
as long as a `SharedArrayBuffer` allocated by it lives.

Refs: https://github.com/nodejs/node/pull/28788
Fixes: https://github.com/nodejs/node/issues/28777
Fixes: https://github.com/nodejs/node/issues/28773

PR-URL: https://github.com/nodejs/node/pull/29190
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

2 files changed, 55 insertions, 0 deletions

diff --git a/test/parallel/test-worker-arraybuffer-zerofill.js b/test/parallel/test-worker-arraybuffer-zerofill.js
new file mode 100644
index 0000000000..3dcf4c006e
--- /dev/null
+++ b/test/parallel/test-worker-arraybuffer-zerofill.js
@@ -0,0 +1,33 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+const { Worker } = require('worker_threads');
+
+// Make sure that allocating uninitialized ArrayBuffers in one thread does not
+// affect the zero-initialization in other threads.
+
+const w = new Worker(`
+const { parentPort } = require('worker_threads');
+
+function post() {
+  const uint32array = new Uint32Array(64);
+  parentPort.postMessage(uint32array.reduce((a, b) => a + b));
+}
+
+setInterval(post, 0);
+`, { eval: true });
+
+function allocBuffers() {
+  Buffer.allocUnsafe(32 * 1024 * 1024);
+}
+
+const interval = setInterval(allocBuffers, 0);
+
+let messages = 0;
+w.on('message', (sum) => {
+  assert.strictEqual(sum, 0);
+  if (messages++ === 100) {
+    clearInterval(interval);
+    w.terminate();
+  }
+});
diff --git a/test/parallel/test-worker-sharedarraybuffer-from-worker-thread.js b/test/parallel/test-worker-sharedarraybuffer-from-worker-thread.js
new file mode 100644
index 0000000000..60e8a5d52a
--- /dev/null
+++ b/test/parallel/test-worker-sharedarraybuffer-from-worker-thread.js
@@ -0,0 +1,22 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const { Worker } = require('worker_threads');
+
+// Regression test for https://github.com/nodejs/node/issues/28777
+// Make sure that SharedArrayBuffers created in Worker threads are accessible
+// after the creating thread ended.
+
+const w = new Worker(`
+const { parentPort } = require('worker_threads');
+const sharedArrayBuffer = new SharedArrayBuffer(4);
+parentPort.postMessage(sharedArrayBuffer);
+`, { eval: true });
+
+let sharedArrayBuffer;
+w.once('message', common.mustCall((message) => sharedArrayBuffer = message));
+w.once('exit', common.mustCall(() => {
+  const uint8array = new Uint8Array(sharedArrayBuffer);
+  uint8array[0] = 42;
+  assert.deepStrictEqual(uint8array, new Uint8Array([42, 0, 0, 0]));
+}));