Bug report

The autoTssKey is deleted during _PyRuntimeState_Fini by gilstate_tss_fini. This isn't safe because other threads may try calling PyGILState_Ensure() or PyGILState_GetThisThreadState() concurrently during shutdown.

	void
	_PyRuntimeState_Fini(_PyRuntimeState *runtime)
	{
	#ifdef Py_REF_DEBUG
	/* The count is cleared by _Py_FinalizeRefTotal(). */
	assert(runtime->object_state.interpreter_leaks == 0);
	#endif

	if (gilstate_tss_initialized(runtime)) {
	gilstate_tss_fini(runtime);
	}

	if (PyThread_tss_is_created(&runtime->trashTSSkey)) {
	PyThread_tss_delete(&runtime->trashTSSkey);
	}
	}

We can:

Convert autoTssKey to a _Py_thread_local like _Py_tss_tstate, which doesn't require deletion
Don't delete autoTssKey at runtime finalization

My preference is for the first option.

cc @ZeroIntensity @ericsnowcurrently @gpshead

Linked PRs

gh-131185: Use a proper thread-local for cached thread states #132510