René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"ffi: stopping a Worker while it is in a callback aborts the process","articleBody":"### Version\n\nmain\n\n### Platform\n\n```text\nmacOS 26.7.0\n```\n\n### Subsystem\n\nffi\n\n### What steps will reproduce the bug?\n\n```js\nimport { Worker } from 'node:worker_threads';\n\n// qsort() from the process image calls the JS comparator through node:ffi.\nconst workerSource = `\nconst { parentPort, workerData } = require('node:worker_threads');\nconst ffi = require('node:ffi');\nconst { lib, functions } = ffi.dlopen(null, {\n  qsort: { arguments: ['pointer', 'u64', 'u64', 'pointer'], return: 'void' },\n});\nconst compare = lib.registerCallback(\n  { arguments: ['pointer', 'pointer'], return: 'i32' },\n  () => {\n    if (workerData === 'exit') process.exit(0);\n    parentPort.postMessage('in callback');\n    for (;;);\n  },\n);\nconst items = new Int32Array([2, 1]);\nfunctions.qsort(ffi.getRawPointer(items), 2n, 4n, compare);\n`;\n\nconst mode = process.argv[2];\nconst worker = new Worker(workerSource, { eval: true, workerData: mode });\nworker.on('message', () => {\n  if (mode === 'shutdown') process.exit(0);\n  worker.terminate();\n});\nworker.on('exit', (code) => console.log(`worker exited with code ${code}`));\n```\n\n```console\n$ node --experimental-ffi repro.mjs shutdown    # main thread calls process.exit(0) while the Worker is in the callback\n$ node --experimental-ffi repro.mjs terminate   # worker.terminate() while the Worker is in the callback\n$ node --experimental-ffi repro.mjs exit        # process.exit() inside the callback\n```\n\n### How often does it reproduce? Is there a required condition?\n\nAlways\n\n### What is the expected behavior? Why is that the expected behavior?\n\nOnly the Worker stops:\n\n```console\n                              # shutdown: exit code 0\nworker exited with code 1     # terminate\nworker exited with code 0     # exit\n```\n\nThe docs say that `process.exit()` in a Worker \"stops the current thread rather than the current process\", and that `worker.terminate()` stops \"JavaScript execution in the worker thread\". Neither of these is an exception thrown by the callback.\n\n### What do you see instead?\n\nAll three modes abort the whole process with exit code 134:\n\n```console\nCallbacks cannot throw an exception\n----- Native stack trace -----\n\n 1: 0x102c5f1b8 node::(anonymous namespace)::DefaultAbortHandler(char const*, char const*) \n 2: 0x102cd8cfc node::ffi::DynamicLibrary::InvokeCallback(ffi_cif*, void*, void**, void*) (.cold.5) \n 3: 0x1008e5bc8 node::ffi::DynamicLibrary::InvokeCallback(ffi_cif*, void*, void**, void*) \n 4: 0x101f5e338 ffi_closure_SYSV_inner\n...\n```\n\n### Additional information\n\n_No response_","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-09-29T05:26:49Z","url":"https://github.com/nodejs/node/issues/66388"}