Native Crash

[hrueger]

Hi, when trying to use this lib on a Windows 10 machine, my application crashed with the following error:

FATAL ERROR: HandleScope::HandleScope Entering the V8 API without proper locking in place
 1: 00007FF6A265B34F v8::internal::CodeObjectRegistry::~CodeObjectRegistry+123599
 2: 00007FF6A25E8CB6 v8::internal::MicrotaskQueue::GetMicrotasksScopeDepth+65206
 3: 00007FF6A25E9D8D node::OnFatalError+301
 4: 00007FF6A2F10A0B v8::HandleScope::Initialize+107
 5: 00007FF6A2EFAFF1 v8::EscapableHandleScope::EscapableHandleScope+81
 6: 00007FF6A262CC78 napi_open_escapable_handle_scope+120
 7: 00007FF9CA33280D Napi::FunctionReference::New+61 [A:\_Source\native-sound-mixer\node_modules\node-addon-api\napi-inl.h]:L3370
 8: 00007FF9CA333663 SoundMixer::DeviceObject::New+83 [A:\_Source\native-sound-mixer\cppsrc\win\sound-mixer.cpp]:L83
 9: 00007FF9CA333465 SoundMixer::MixerObject::GetDevices+341 [A:\_Source\native-sound-mixer\cppsrc\win\sound-mixer.cpp]:L4710: 00007FF9CA336A3E Napi::details::WrapCallback<<lambda_2d6a469e53703925d71c48cc7e420a87> >+46 [A:\_Source\native-sound-mixer\node_modules\node-addon-api\napi-inl.h]:L75
11: 00007FF9CA335F58 Napi::details::TemplatedCallback<&SoundMixer::MixerObject::GetDevices>+40 [A:\_Source\native-sound-mixer\node_modules\node-addon-api\napi-inl.h]:L153
12: 00007FF6A262564B node::Stop+32747
13: 00007FF6A2F3E74F v8::internal::SetupIsolateDelegate::SetupHeap+53823
14: 00007FF6A2F6FAE9 v8::internal::SetupIsolateDelegate::SetupHeap+255449
15: 000002D94CCBDBBE

Any idea?

[m1dugh]

could you show me your node code causing this crash ?

[hrueger]

Thanks for the fast response. I'll try to find the exact call. It's a pretty complex project, it might take a while.

[hrueger]

So, I've finally found it. This is the code:

const SoundMixer = require("native-sound-mixer").default;
const pollInterval = setInterval(() => {
    for (const device of SoundMixer.devices) {
        console.log(device, device.volume);
    }
}, 500);

It works find for the first 6 iterations, then in the 7th one it crashes. However, I was not able to reproduce that in a standalone example, I don't know why. It is definitely that line, though, as it works fine if I comment it out. It does not matter if I read the mute or the volume property by the way.

[m1dugh]

Are you using the call in a multi threaded context ? It looks like the problem is the same as this one https://github.com/nodejs/node-addon-api/issues/779. I can hardly fix the code right now, i'll try to make it as fast as I can.

[hrueger]

I am using Worker Threads on my application, but this library is used in the main thread.

[m1dugh]

I might have located the problem, i'll try to fix it as soon as possible.

[hrueger]

Thanks in advance!

[m1dugh]

Since the bug is not reproductible in a standalone, it will be hard to test the code on my side. I can still push the fix on develop and you can test it before I push a new version if that's ok for you 😄. Otherwise, I will push the fix to a new version on npm registry but I can't be sure it will fix the problem ...

[hrueger]

I can still push the fix on develop and you can test it before I push a new version if that's ok for you

Sure 👍

[m1dugh]

It took longer than I expected, I should be done by next week I guess.

[hrueger]

No problem, thanks for your efforts 👍

[m1dugh]

I pushed something to 20-native-crash branch, I have no clue whether it might be better but you can try anyway.

[hrueger]

Hm, I can't even reproduce the original error anymore... Very strange.

However, while testing, I found that there may be a memory leak? Not sure, though. If you run the following code, you can see the memory usage of the Node Process increasing by about 1MB / s. Maybe this gives a hint? Could also be completely unreleated, though ;-)

const nsm = require("native-sound-mixer").default;

let mute;
let volume;
(async () => {
    while (true) {
        console.log("next round")
        for (let i = 0; i < 1000; i++) {
            for (const device of nsm.devices) {
                mute = device.mute;
                volume = device.volume;
            }
        }
        await new Promise((resolve) => { setTimeout(() => { resolve(); }, 500); });
    }
})();

[m1dugh]

If you can't reproduce the original error, I hope it was some strange node issue. Concerning the memory leak problem, I'm currently working on it. However, due to the way node handles memory, the memory should be flushed regularly, fixing the memory leak as it goes.

[hrueger]

I hope it was some strange node issue

I agree 👍

Concerning the memory leak problem, I'm currently working on it.

Thanks a lot

[m1dugh]

The memory leaks concerning the devices should be fixed on develop (for windows only)

[hrueger]

Yes, can confirm that the memory leak is gone 👍 Thanks for your effort.