gh-149459: Fix segfault when _LOAD_SPECIAL guard deoptimizes#149478
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kumaraditya303 merged 6 commits intopython:mainfrom May 8, 2026
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gh-149459: Fix segfault when _LOAD_SPECIAL guard deoptimizes#149478kumaraditya303 merged 6 commits intopython:mainfrom
kumaraditya303 merged 6 commits intopython:mainfrom
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markshannon
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May 7, 2026
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Looks good. Thanks for fixing this
kumaraditya303
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May 8, 2026
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Thanks @cocolato for the PR, and @kumaraditya303 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.15. |
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GH-149552 is a backport of this pull request to the 3.15 branch. |
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…GH-149478) (#149552) gh-149459: Fix segfault when `_LOAD_SPECIAL` guard deoptimizes (GH-149478) (cherry picked from commit c341e34) Co-authored-by: Hai Zhu <haiizhu@outlook.com>
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LOAD_SPECIALexpands as:_RECORD_TOS_TYPE + _INSERT_NULL + _LOAD_SPECIAL_INSERT_NULLalters the actual stack structure:Before modification:
[..., self]After modification:
[..., NULL, self]The optimizer has introduced
_GUARD_TYPE_VERSION. If a guard is placed after_INSERT_NULL, and the guard fails resulting in a side exit, the interpreter will deopt back to the originalLOAD_SPECIAL. However, by this point, the stack has already been modified by_INSERT_NULLto[..., NULL, self]._PyObject_LookupSpecialMethod#149459