gh-130091: Reorder _PyThreadState_Attach to avoid data race#130092
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This moves `tstate_activate()` down to avoid a data race in the free threading build on the `_PyRuntime`'s thread-local `autoTSSkey`. This key is deleted during runtime finalization, which may happen concurrently with a call to `_PyThreadState_Attach`. The earlier `tstate_try/wait_attach` ensures that the thread is blocked before it attempts to access the deleted `autoTSSkey`. This fixes a TSAN reported data race in `test_threading.test_import_from_another_thread`.
mpage
approved these changes
Feb 27, 2025
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This moves
tstate_activate()down to avoid a data race in the free threading build on the_PyRuntime's thread-localautoTSSkey. This key is deleted during runtime finalization, which may happen concurrently with a call to_PyThreadState_Attach.The earlier
tstate_try/wait_attachensures that the thread is blocked before it attempts to access the deletedautoTSSkey.This fixes a TSAN reported data race in
test_threading.test_import_from_another_thread.PyThread_tss_deleteand_PyThreadState_Attach#130091