gh-152375: Fix UB in INSTRUMENTED_JUMP#152376
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This was referenced Jun 27, 2026
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iritkatriel
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Jun 27, 2026
| stack_pointer = _PyFrame_GetStackPointer(frame); \ | ||
| if (next_instr == NULL) { \ | ||
| next_instr = (dest)+1; \ | ||
| next_instr = _dest + 1; \ |
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What does this do? Is it the same as just casting dest to _Py_CODEUNIT?
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This is a macro, where dest expands to next_instr + oparg:
cpython/Python/generated_cases.c.h
Line 8158 in b3154aa
(The issue has more detail on this.)
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But I don't understand the fix. It looks like just a rename.
iritkatriel
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Jun 27, 2026
StanFromIreland
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needs backport to 3.13
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I didn't add a test, I think it's too messy here, but I don't feel strongly about it. It is also already covered (non-deterministically) by
test_monitoring, as that's what triggered UBSan.