Crash during Incremental marking / GC round

[fkp...@gmail.com]

Hi all,
I'm writing an addon to node - which creates multiple additional multiple threads, each holding a seperate isolate (and event loop and other goodies).
Now, I use promises to let the main thread - running in node v8 isolate to know that each of the secondery threads have started and use RunMicroTasks().

After a minute or two - i get the following exceptions:


Any clue on why? how?
How can i trace the source to such issue?