[3.14] gh-148144: Initialize visited on copied interpreter frames (GH-148143)#148147
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pablogsal merged 1 commit intopython:3.14from Apr 5, 2026
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…honGH-148143) _PyFrame_Copy() copied interpreter frames into generator and frame-object storage without initializing the visited byte. Incremental GC later reads frame->visited in mark_stacks() on non-start passes, so copied frames could expose an uninitialized value once they became live on a thread stack again. Reset visited when copying a frame so copied frames start with defined GC bookkeeping state. Preserve lltrace in Py_DEBUG builds. (cherry picked from commit fbfc6ccb0abf362a0ecdc02cd0aa2d16c1a4ce44) Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
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_PyFrame_Copy() copied interpreter frames into generator and
frame-object storage without initializing the visited byte. Incremental
GC later reads frame->visited in mark_stacks() on non-start passes, so
copied frames could expose an uninitialized value once they became live
on a thread stack again.
Reset visited when copying a frame so copied frames start with defined
GC bookkeeping state. Preserve lltrace in Py_DEBUG builds.
(cherry picked from commit fbfc6cc)
Co-authored-by: Pablo Galindo Salgado Pablogsal@gmail.com
frame->visitedis used uninitialized inmark_stacks#148144