From: #281 (comment)

It looks like this happens because the thread is deleted by DLLMain
https://github.com/ivmai/bdwgc/blob/2558568aceaf7fc5cc64cf87e244cbcfd7f9bd53/win32_threads.c#L3009

Somehow this happens at the same time as the GC_gcollect call within neko_gc_major() while neko is shutting down, which also tries to access the same thread to suspend it.

Can be reproduced by running this program repeatedly:

function main() {
	final lock = new sys.thread.Lock();
	sys.thread.Thread.create(function() {
		lock.release();
	});
	lock.wait();
}

Here is a minimal sample. For this to reproduce the following conditions must be met:

• App must contain thread
• Thread must complete before the main thread
• DllMain call for detaching thread must be interleaved with a GC_gcollect call in neko_gc_major()

See: bdwgc/bdwgc#704