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gh-137433: Fix deadlock with stop-the-world and daemon threads (gh-137735)

There was a deadlock originally seen by Memray when a daemon thread
enabled or disabled profiling while the interpreter was shutting down.
I think this could also happen with garbage collection, but I haven't
seen that in practice.

The daemon thread could be hung while trying acquire the global rwmutex
that prevents overlapping global and per-interpreter stop-the-world events.
Since it already held the main interpreter's stop-the-world lock, it
also deadlocked the main thread, which is trying to perform interpreter
finalization.

Swap the order of lock acquisition to prevent this deadlock.
Additionally, refactor `_PyParkingLot_Park` so that the global buckets
hashtable is left in a clean state if the thread is hung in
`PyEval_AcquireThread`.
S
Sam Gross committed
90fe3250f82712b61630d636246c92df7c40c816
Parent: 4c0d7bc
Committed by GitHub <noreply@github.com> on 9/16/2025, 8:21:58 AM