parallel/test-domain-error-types can crash if GC timings get unlucky #28275

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1. addaleax

   added

   domainIssues and PRs related to the domain subsystem.Issues and PRs related to the domain subsystem.

   confirmed-bugIssues and PRs for confirmed bugs.Issues and PRs for confirmed bugs.

   on Jun 19, 2019
2. addaleax commented on Jun 19, 2019

   

   addaleax

   on Jun 19, 2019

   Last edited by addaleax

   Member

   More actions

   Thanks for the bug report, this is something I definitely missed.

   I can’t reproduce the issue without a debug build, so testing this out is going to take a while, but something like this might help:

   diff --git a/lib/domain.js b/lib/domain.js
   index b2ffed2741bc..3dc56c179aca 100644
   --- a/lib/domain.js
   +++ b/lib/domain.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) {
   diff --git a/src/node_util.cc b/src/node_util.cc
   index 518865fe5368..fa39583b04ba 100644
   --- a/src/node_util.cc
   +++ b/src/node_util.cc
   @@ -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();
   
3. addaleax commented on Jun 20, 2019

   

   addaleax

   on Jun 20, 2019

   Member

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   Actually, I think this may have been caused by #26211 because the domain is now no longer kept alive through the domain stack. I’ll open a PR with the above suggestion, it does seem to resolve the issue.
4. addaleax

   added a commit that references this issue on Jun 20, 2019

   domain: use strong reference to domain while active

   ...

   302fc52
5. Trott

   added a commit that references this issue on Jul 25, 2019

   domain: use strong reference to domain while active

   ...

   43e5478
6. Trott

   closed this as completedin 43e5478on Jul 25, 2019
7. gntem

   added a commit that references this issue on Jul 27, 2019

   domain: use strong reference to domain while active

   ...

   d1bbdda
8. targos

   added a commit that references this issue on Aug 2, 2019

   domain: use strong reference to domain while active

   ...

   727ffe4
9. vikashk1

   added a commit that references this issue on Aug 13, 2019

   Please ignore this msg (#1)

   ...

   9af17ad