gh-136421: Fix crash when _datetime is been initialized in multiple sub-interpreters

[aisk]

• Issue: Import _datetime in sub-interpreters in the same time may crash the process #136421

[ZeroIntensity]

I think we need a more fundamental fix that prevents static types from being initialized concurrently. This is sort of a known issue, see #129817.

[ZeroIntensity]

If the assumption is that this can run concurrently, then we need to also protect the assignments to tp_base above.

[bedevere-app]

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[neonene]

A lock needs to be applied to whole the loop or function rather than to a type to avoid a crash here (for me), because all managed static extension types are currently supposed to be indexed by using the same interpreter:

cpython/Objects/typeobject.c

Lines 322 to 329 in db47f4d

	else {
	PyMutex_Lock(&interp->types.mutex);
	index = interp->types.for_extensions.next_index;
	interp->types.for_extensions.next_index++;
	PyMutex_Unlock(&interp->types.mutex);
	assert(index < _Py_MAX_MANAGED_STATIC_EXT_TYPES);
	}
	managed_static_type_index_set(self, index);

[neonene]

A lock needs to be applied to whole the loop or function

Hmm, still crashes with many workers...