René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"SEGV functools _Py_dict_lookup","articleBody":"# Crash report\n\n### What happened?\n\n```python\nimport functools\nimport unittest\ndef capture(*args, **kw):\n    return (args, kw)\ndef extract_sig(part):\n    return (part.func, part.args, part.keywords, part.__dict__)\nclass MyTuple(tuple):\n    def __add__(self, other):\n        return list(self) + list(other)\nclass MyDict(dict):\n    pass\nclass TestPartialSetstateSubclasses(unittest.TestCase):\n        f = functools.partial(extract_sig)\n        f.__setstate__((capture, MyTuple((1,)), MyDict(a=10), '\\u2603'))\n        f.__setstate__((capture, BadTuple((1,)), {}, None))\nif __name__ == \"__main__\":\n    import unittest; unittest.main(verbosity=0)\n```\n\n```\nAddressSanitizer:DEADLYSIGNAL\n=================================================================\n==197163==ERROR: AddressSanitizer: SEGV on unknown address (pc 0x583829da5bda bp 0x7ffd359603d0 sp 0x7ffd35960320 T0)\n==197163==The signal is caused by a READ memory access.\n==197163==Hint: this fault was caused by a dereference of a high value address (see register values below).  Disassemble the provided pc to learn which register was used.\n    #0 0x583829da5bda in _Py_dict_lookup ../Objects/dictobject.c:1254\n    #1 0x583829dae83f in _Py_dict_lookup_threadsafe ../Objects/dictobject.c:1643\n    #2 0x583829dae83f in _PyDict_GetMethodStackRef ../Objects/dictobject.c:1691\n    #3 0x583829dfc2ff in _PyObject_GetMethodStackRef ../Objects/object.c:1756\n    #4 0x583829b831a4 in _PyEval_EvalFrameDefault ../Python/generated_cases.c.h:7844\n    #5 0x58382a057b55 in _PyEval_EvalFrame ../Include/internal/pycore_ceval.h:121\n    #6 0x58382a057b55 in _PyEval_Vector ../Python/ceval.c:2001\n    #7 0x58382a0439e8 in builtin___build_class__ ../Python/bltinmodule.c:205\n    #8 0x583829cd2ee7 in _PyObject_VectorcallTstate ../Include/internal/pycore_call.h:169\n    #9 0x583829cd2ee7 in PyObject_Vectorcall ../Objects/call.c:327\n    #10 0x583829b74ad2 in _PyEval_EvalFrameDefault ../Python/generated_cases.c.h:1620\n    #11 0x58382a057386 in _PyEval_EvalFrame ../Include/internal/pycore_ceval.h:121\n    #12 0x58382a057386 in _PyEval_Vector ../Python/ceval.c:2001\n    #13 0x58382a057386 in PyEval_EvalCode ../Python/ceval.c:884\n    #14 0x58382a215f0e in run_eval_code_obj ../Python/pythonrun.c:1365\n    #15 0x58382a215f0e in run_mod ../Python/pythonrun.c:1459\n    #16 0x58382a21abb7 in pyrun_file ../Python/pythonrun.c:1293\n    #17 0x58382a21abb7 in _PyRun_SimpleFileObject ../Python/pythonrun.c:521\n    #18 0x58382a21b6dc in _PyRun_AnyFileObject ../Python/pythonrun.c:81\n    #19 0x58382a28eafc in pymain_run_file_obj ../Modules/main.c:410\n    #20 0x58382a28eafc in pymain_run_file ../Modules/main.c:429\n    #21 0x58382a28eafc in pymain_run_python ../Modules/main.c:691\n    #22 0x58382a2903de in Py_RunMain ../Modules/main.c:772\n    #23 0x58382a2903de in pymain_main ../Modules/main.c:802\n    #24 0x58382a2903de in Py_BytesMain ../Modules/main.c:826\n    #25 0x7249b00571c9  (/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9) (BuildId: 282c2c16e7b6600b0b22ea0c99010d2795752b5f)\n    #26 0x7249b005728a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28a) (BuildId: 282c2c16e7b6600b0b22ea0c99010d2795752b5f)\n\nAddressSanitizer can not provide additional info.\nSUMMARY: AddressSanitizer: SEGV ../Objects/dictobject.c:1254 in _Py_dict_lookup\n==197163==ABORTING\n```\n\n### CPython versions tested on:\n\nCPython main branch\n\n### Operating systems tested on:\n\nLinux\n\n### Output from running 'python -VV' on the command line:\n\n_No response_\n\n\u003c!-- gh-linked-prs -->\n### Linked PRs\n* gh-140671\n* gh-140698\n* gh-140699\n\u003c!-- /gh-linked-prs -->\n","author":{"url":"https://github.com/YuanchengJiang","@type":"Person","name":"YuanchengJiang"},"datePublished":"2025-10-25T15:22:21Z","url":"https://github.com/python/cpython/issues/140590"}