gh-144356: fix data race in setiter_len() under no-gil
#144357
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setiter_len() was reading so->used without atomic access while concurrent mutations update it atomically under Py_GIL_DISABLED. Use an atomic load for so->used to avoid a data race. This preserves the existing semantics of __length_hint__ while making the access thread-safe. Signed-off-by: Yongtao Huang <[email protected]>
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Long log:
setiter_len()was readingso->usedwithout atomic access while concurrentmutations update it atomically under Py_GIL_DISABLED.
Use an atomic load for
so->usedto avoid a data race. This preserves theexisting semantics of
__length_hint__while making the access thread-safe.Signed-off-by: Yongtao Huang [email protected]