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domain: use strong reference to domain while active

When an uncaught exception is thrown inside a domain, the domain is
removed from the stack as of 43a5170.
This means that it might not be kept alive as an object anymore,
and may be garbage collected before the `after()` hook can run,
which tries to exit it as well.

Resolve that by making references to the domain strong while it is
active.

Fixes: #28275

PR-URL: #28313
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Vladimir de Turckheim <vlad2t@hotmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
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addaleax authored and targos committed Jun 20, 2019
1 parent ae56a23 commit 727ffe472068be1093a3f2d9f7f1238852166ac0
Showing with 25 additions and 1 deletion.
  1. +6 −1 lib/domain.js
  2. +16 −0 src/node_util.cc
  3. +3 −0 test/parallel/test-domain-error-types.js
@@ -73,13 +73,18 @@ const asyncHook = createHook({
if (current !== undefined) { // Enter domain for this cb
// We will get the domain through current.get(), because the resource
// object's .domain property makes sure it is not garbage collected.
// However, we do need to make the reference to the domain non-weak,
// so that it cannot be garbage collected before the after() hook.
current.incRef();
current.get().enter();
}
},
after(asyncId) {
const current = pairing.get(asyncId);
if (current !== undefined) { // Exit domain for this cb
current.get().exit();
const domain = current.get();
current.decRef();
domain.exit();
}
},
destroy(asyncId) {
@@ -189,12 +189,26 @@ class WeakReference : public BaseObject {
args.GetReturnValue().Set(weak_ref->target_.Get(isolate));
}

static void IncRef(const FunctionCallbackInfo<Value>& args) {
WeakReference* weak_ref = Unwrap<WeakReference>(args.Holder());
if (weak_ref->reference_count_ == 0) weak_ref->target_.ClearWeak();
weak_ref->reference_count_++;
}

static void DecRef(const FunctionCallbackInfo<Value>& args) {
WeakReference* weak_ref = Unwrap<WeakReference>(args.Holder());
CHECK_GE(weak_ref->reference_count_, 1);
weak_ref->reference_count_--;
if (weak_ref->reference_count_ == 0) weak_ref->target_.SetWeak();
}

SET_MEMORY_INFO_NAME(WeakReference)
SET_SELF_SIZE(WeakReference)
SET_NO_MEMORY_INFO()

private:
Global<Object> target_;
uint64_t reference_count_ = 0;
};

static void GuessHandleType(const FunctionCallbackInfo<Value>& args) {
@@ -294,6 +308,8 @@ void Initialize(Local<Object> target,
weak_ref->InstanceTemplate()->SetInternalFieldCount(1);
weak_ref->SetClassName(weak_ref_string);
env->SetProtoMethod(weak_ref, "get", WeakReference::Get);
env->SetProtoMethod(weak_ref, "incRef", WeakReference::IncRef);
env->SetProtoMethod(weak_ref, "decRef", WeakReference::DecRef);
target->Set(context, weak_ref_string,
weak_ref->GetFunction(context).ToLocalChecked()).Check();

@@ -1,3 +1,4 @@
// Flags: --gc-interval=100 --stress-compaction
'use strict';

const common = require('../common');
@@ -6,6 +7,8 @@ const domain = require('domain');

// This test is similar to test-domain-multiple-errors, but uses a new domain
// for each errors.
// The test flags are not essential, but serve as a way to verify that
// https://github.com/nodejs/node/issues/28275 is fixed in debug mode.

for (const something of [
42, null, undefined, false, () => {}, 'string', Symbol('foo')

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