lib: properly processing JavaScript exceptions on async_hooks fatal e…

…rror

JavaScript exceptions could be arbitrary values.

lib/internal/async_hooks.js

@@ -158,7 +158,7 @@ function executionAsyncResource() {
 
 // Used to fatally abort the process if a callback throws.
 function fatalError(e) {
-  if (typeof e.stack === 'string') {
+  if (e !== null && typeof e === 'object' && typeof e.stack === 'string') {
     process._rawDebug(e.stack);
   } else {
     const o = { message: e };

test/parallel/test-async-hooks-fatal-error.js

@@ -0,0 +1,42 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+const childProcess = require('child_process');
+
+if (process.argv[2] === 'child') {
+  child(process.argv[3]);
+} else {
+  main();
+}
+
+function child(type) {
+  const { createHook } = require('async_hooks');
+  const fs = require('fs');
+
+  createHook({
+    [type]() {
+      // eslint-disable-next-line no-throw-literal
+      throw null;
+    }
+  }).enable();
+
+  // Trigger `promiseResolve`.
+  new Promise((resolve) => resolve())
+  // Trigger `after`/`destroy`.
+    .then(() => fs.promises.readFile(__filename, 'utf8'))
+  // Make process exit with code 0 if no error caught.
+    .then(() => process.exit(0));
+}
+
+function main() {
+  const types = [ 'init', 'before', 'after', 'destroy', 'promiseResolve' ];
+  for (const type of types) {
+    const cp = childProcess.spawnSync(process.execPath,
+                                      [ __filename, 'child', type ],
+                                      {
+                                        encoding: 'utf8',
+                                      });
+    assert.strictEqual(cp.status, 1, type);
+    assert.strictEqual(cp.stderr.trim().split('\n')[0], 'Error: null', type);
+  }
+}