gh-154672: Fix use-after-free in itertools.zip_longest via re-entrant iterator#154673
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tonghuaroot wants to merge 5 commits into
Open
gh-154672: Fix use-after-free in itertools.zip_longest via re-entrant iterator#154673tonghuaroot wants to merge 5 commits into
tonghuaroot wants to merge 5 commits into
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I already have an open PR that would fix this use-after-free (#150675), |
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zip_longest_next_lock_held()borrows iterators fromlz->ittupleviaPyTuple_GET_ITEMwithoutPy_INCREF, then callsPyIter_Next(it). A re-entrant callback can exhaust and free the iterator while the outer call is still using it.Fix:
Py_INCREF(it)beforePyIter_Next,Py_DECREFafter. Guard the exhaust handler against double-free when a re-entrant call already removed the iterator.