Bug report

Bug description:

There is a potential race when_PyParkingLot_UnparkAll is executing in one thread and another thread is unblocked because of an interrupt in_PyParkingLot_Park. Consider the following scenario:

1. Thread T0 isblocked in_PyParkingLot_Park on addressA.
2. Thread T1 executes_PyParkingLot_UnparkAll on addressA. It finds thewait_entry forT0 andunlinks its list node.
3. Immediately after (2), T0 is woken up due to an interrupt. It then segfaults trying tounlink the node that was previously unlinked in (2).

I haven't attempted to write a minimal repro for this. It occurs reliably on MacOS onthis PR when running./python.exe -m test test_asyncio.test_events --match test_get_event_loop_new_process.

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Linked PRs

• gh-114944: Fix race between_PyParkingLot_Park and_PyParkingLot_UnparkAll when handling interrupts #114945