Your callstack is very strange. At line 30 of main.cpp GIL is obviously locked:


   // importing module in this tread
   gstate = PyGILState_Ensure();
   py::module crash_test = py::module::import( "crash_test" ); <-- import
   PyGILState_Release( gstate );

I suppose that there is something wrong with your setup. Maybe - wrong working directory for the main executable, which doesn't contain crash_test.py

Also I've tried to revert this patch https://github.com/python/cpython/pull/5278 for 3.7. It makes problem to disappear, 1 hour of stable work under ASAN. So I suppose it is the source of the bug.

I will try to tweak _testembed.c.