diff --git a/Include/internal/pycore_interpframe.h b/Include/internal/pycore_interpframe.h index 8db1aebdc11401..d744dd12cd0479 100644 --- a/Include/internal/pycore_interpframe.h +++ b/Include/internal/pycore_interpframe.h @@ -149,6 +149,11 @@ static inline void _PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame * int stacktop = (int)(src->stackpointer - src->localsplus); assert(stacktop >= 0); dest->stackpointer = dest->localsplus + stacktop; + // visited is GC bookkeeping for the current stack walk, not frame state. + dest->visited = 0; +#ifdef Py_DEBUG + dest->lltrace = src->lltrace; +#endif for (int i = 0; i < stacktop; i++) { dest->localsplus[i] = PyStackRef_MakeHeapSafe(src->localsplus[i]); } diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-04-05-15-20-00.gh-issue-148144.f7qA0x.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-05-15-20-00.gh-issue-148144.f7qA0x.rst new file mode 100644 index 00000000000000..beda992a95bf94 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-05-15-20-00.gh-issue-148144.f7qA0x.rst @@ -0,0 +1,3 @@ +Initialize ``_PyInterpreterFrame.visited`` when copying interpreter frames so +incremental GC does not read an uninitialized byte from generator and +frame-object copies.