[3.13] gh-117657: Fix race involving GC and heap initialization (GH-119923) #120038
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…nGH-119923) The `_PyThreadState_Bind()` function is called before the first `PyEval_AcquireThread()` so it's not synchronized with the stop the world GC. We had a race where `gc_visit_heaps()` might visit a thread's heap while it's being initialized. Use a simple atomic int to avoid visiting heaps for threads that are not yet fully initialized (i.e., before `tstate_mimalloc_bind()` is called). The race was reproducible by running: `python Lib/test/test_importlib/partial/pool_in_threads.py`. (cherry picked from commit e69d068) Co-authored-by: Sam Gross <colesbury@gmail.com>
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The
_PyThreadState_Bind()function is called before the firstPyEval_AcquireThread()so it's not synchronized with the stop theworld GC. We had a race where
gc_visit_heaps()might visit a thread'sheap while it's being initialized.
Use a simple atomic int to avoid visiting heaps for threads that are not
yet fully initialized (i.e., before
tstate_mimalloc_bind()is called).The race was reproducible by running:
python Lib/test/test_importlib/partial/pool_in_threads.py.(cherry picked from commit e69d068)
Co-authored-by: Sam Gross colesbury@gmail.com