python3.10.12 crashed on powerpc 32bit system when PyGC_Collect()

[fduan001]

Crash report

What happened?

^@(gdb)
#0  _PyObject_IS_GC (obj=0x80000000) at ../Python-3.10.13/Include/internal/pycore_object.h:165
#1  visit_decref (op=0x80000000, parent=parent@entry=0xb78a5b18) at ../Python-3.10.13/Modules/gcmodule.c:456
#2  0x0fe3297c in abc_data_traverse (self=0xb78a5b18, visit=0xfdee5e0 <visit_decref>, arg=0xb78a5b18) at ../Python-3.10.13/Modules/_abc.c:52
#3  0x0fdef3cc in subtract_refs (containers=<optimized out>) at ../Python-3.10.13/Modules/gcmodule.c:482
#4  deduce_unreachable (unreachable=0xbfedad4c, base=<optimized out>) at ../Python-3.10.13/Modules/gcmodule.c:1105
#5  gc_collect_main (tstate=tstate@entry=0x10030030, generation=generation@entry=2, n_collected=n_collected@entry=0xbfedadcc,
    n_uncollectable=n_uncollectable@entry=0xbfedadc8, nofail=nofail@entry=0) at ../Python-3.10.13/Modules/gcmodule.c:1239
#6  0x0fdf00e0 in gc_collect_with_callback (tstate=tstate@entry=0x10030030, generation=generation@entry=2)
    at ../Python-3.10.13/Modules/gcmodule.c:1413
#7  0x0fdf08f8 in PyGC_Collect () at ../Python-3.10.13/Modules/gcmodule.c:2099
#8  0x0fdc0430 in Py_FinalizeEx () at ../Python-3.10.13/Python/pylifecycle.c:1781
#9  Py_FinalizeEx () at ../Python-3.10.13/Python/pylifecycle.c:1703
#10 0x0fdc146c in Py_Exit (sts=0) at ../Python-3.10.13/Python/pylifecycle.c:2858
#11 0x0fdc791c in handle_system_exit () at ../Python-3.10.13/Python/pythonrun.c:775
#12 _PyErr_PrintEx (tstate=0x10030030, set_sys_last_vars=set_sys_last_vars@entry=1) at ../Python-3.10.13/Python/pythonrun.c:785
#13 0x0fdc7980 in PyErr_PrintEx (set_sys_last_vars=set_sys_last_vars@entry=1) at ../Python-3.10.13/Python/pythonrun.c:880
#14 0x0fdc79a8 in PyErr_Print () at ../Python-3.10.13/Python/pythonrun.c:886
#15 0x0fdc8170 in _PyRun_SimpleFileObject (fp=fp@entry=0x10021430, filename=filename@entry=0xb78105a0, closeit=closeit@entry=1,
    flags=flags@entry=0xbfedafb0) at ../Python-3.10.13/Python/pythonrun.c:462
#16 0x0fdc84f4 in _PyRun_AnyFileObject (fp=fp@entry=0x10021430, filename=filename@entry=0xb78105a0, closeit=closeit@entry=1,
    flags=flags@entry=0xbfedafb0) at ../Python-3.10.13/Python/pythonrun.c:90
#17 0x0fded70c in pymain_run_file_obj (skip_source_first_line=0, filename=0xb78105a0, program_name=0xb78fbee0)
    at ../Python-3.10.13/Modules/main.c:353
#18 pymain_run_file (config=0x10021ff4) at ../Python-3.10.13/Modules/main.c:372
#19 pymain_run_python (exitcode=0xbfedafb8) at ../Python-3.10.13/Modules/main.c:587
#20 Py_RunMain () at ../Python-3.10.13/Modules/main.c:666
#21 0x0fdedbcc in pymain_main (args=args@entry=0xbfedb048) at ../Python-3.10.13/Modules/main.c:696
#22 0x0fdedcb0 in Py_BytesMain (argc=<optimized out>, argv=<optimized out>) at ../Python-3.10.13/Modules/main.c:720
#23 0x10000474 in main (argc=<optimized out>, argv=<optimized out>) at ../Python-3.10.13/Programs/python.c:15

CPython versions tested on:

3.10

Operating systems tested on:

Linux

Output from running 'python -VV' on the command line:

Python 3.10.13 (main, Aug 24 2023, 12:59:26) [GCC 11.4.0]

[fduan001]

^@(gdb)
#0  _PyObject_IS_GC (obj=0x80000000) at ../Python-3.10.13/Include/internal/pycore_object.h:165
#1  visit_decref (op=0x80000000, parent=parent@entry=0xb78a5b18) at ../Python-3.10.13/Modules/gcmodule.c:456
#2  0x0fe3297c in abc_data_traverse (self=0xb78a5b18, visit=0xfdee5e0 <visit_decref>, arg=0xb78a5b18) at ../Python-3.10.13/Modules/_abc.c:52
#3  0x0fdef3cc in subtract_refs (containers=<optimized out>) at ../Python-3.10.13/Modules/gcmodule.c:482
#4  deduce_unreachable (unreachable=0xbfedad4c, base=<optimized out>) at ../Python-3.10.13/Modules/gcmodule.c:1105
#5  gc_collect_main (tstate=tstate@entry=0x10030030, generation=generation@entry=2, n_collected=n_collected@entry=0xbfedadcc,
    n_uncollectable=n_uncollectable@entry=0xbfedadc8, nofail=nofail@entry=0) at ../Python-3.10.13/Modules/gcmodule.c:1239
#6  0x0fdf00e0 in gc_collect_with_callback (tstate=tstate@entry=0x10030030, generation=generation@entry=2)
    at ../Python-3.10.13/Modules/gcmodule.c:1413
#7  0x0fdf08f8 in PyGC_Collect () at ../Python-3.10.13/Modules/gcmodule.c:2099
#8  0x0fdc0430 in Py_FinalizeEx () at ../Python-3.10.13/Python/pylifecycle.c:1781
#9  Py_FinalizeEx () at ../Python-3.10.13/Python/pylifecycle.c:1703
#10 0x0fdc146c in Py_Exit (sts=0) at ../Python-3.10.13/Python/pylifecycle.c:2858
#11 0x0fdc791c in handle_system_exit () at ../Python-3.10.13/Python/pythonrun.c:775
#12 _PyErr_PrintEx (tstate=0x10030030, set_sys_last_vars=set_sys_last_vars@entry=1) at ../Python-3.10.13/Python/pythonrun.c:785
#13 0x0fdc7980 in PyErr_PrintEx (set_sys_last_vars=set_sys_last_vars@entry=1) at ../Python-3.10.13/Python/pythonrun.c:880
#14 0x0fdc79a8 in PyErr_Print () at ../Python-3.10.13/Python/pythonrun.c:886
#15 0x0fdc8170 in _PyRun_SimpleFileObject (fp=fp@entry=0x10021430, filename=filename@entry=0xb78105a0, closeit=closeit@entry=1,
    flags=flags@entry=0xbfedafb0) at ../Python-3.10.13/Python/pythonrun.c:462
#16 0x0fdc84f4 in _PyRun_AnyFileObject (fp=fp@entry=0x10021430, filename=filename@entry=0xb78105a0, closeit=closeit@entry=1,
    flags=flags@entry=0xbfedafb0) at ../Python-3.10.13/Python/pythonrun.c:90
#17 0x0fded70c in pymain_run_file_obj (skip_source_first_line=0, filename=0xb78105a0, program_name=0xb78fbee0)
    at ../Python-3.10.13/Modules/main.c:353
#18 pymain_run_file (config=0x10021ff4) at ../Python-3.10.13/Modules/main.c:372
#19 pymain_run_python (exitcode=0xbfedafb8) at ../Python-3.10.13/Modules/main.c:587
#20 Py_RunMain () at ../Python-3.10.13/Modules/main.c:666
#21 0x0fdedbcc in pymain_main (args=args@entry=0xbfedb048) at ../Python-3.10.13/Modules/main.c:696
#22 0x0fdedcb0 in Py_BytesMain (argc=<optimized out>, argv=<optimized out>) at ../Python-3.10.13/Modules/main.c:720
#23 0x10000474 in main (argc=<optimized out>, argv=<optimized out>) at ../Python-3.10.13/Programs/python.c:15
(gdb)

[fduan001]

(gdb) bt
#0  PyType_HasFeature (feature=<optimized out>, type=<optimized out>) at ../Python-3.10.13/Objects/dictobject.c:1826
#1  _PyDict_Next (op=0x40, ppos=0xbfbedf78, pkey=0x0, pvalue=0xbfbedf7c, phash=0x0) at ../Python-3.10.13/Objects/dictobject.c:1826
#2  0x0fcaf458 in PyDict_Next (op=op@entry=0x40, ppos=ppos@entry=0xbfbedf78, pkey=pkey@entry=0x0, pvalue=pvalue@entry=0xbfbedf7c)
    at ../Python-3.10.13/Objects/dictobject.c:1882
#3  0x0fce24d4 in PyType_Modified (type=0xffd8588 <PyBytesIO_Type>) at ../Python-3.10.13/Objects/typeobject.c:343
#4  PyType_Modified (type=0xffd8588 <PyBytesIO_Type>) at ../Python-3.10.13/Objects/typeobject.c:316
#5  0x0fce2504 in PyType_Modified (type=0xffd8c04 <PyBufferedIOBase_Type>) at ../Python-3.10.13/Objects/typeobject.c:347
#6  PyType_Modified (type=0xffd8c04 <PyBufferedIOBase_Type>) at ../Python-3.10.13/Objects/typeobject.c:316
#7  0x0fce2504 in PyType_Modified (type=0xffd7f78 <PyIOBase_Type>) at ../Python-3.10.13/Objects/typeobject.c:347
#8  PyType_Modified (type=0xffd7f78 <PyIOBase_Type>) at ../Python-3.10.13/Objects/typeobject.c:316
#9  0x0fce2504 in PyType_Modified (type=0xffcd098 <PyBaseObject_Type>) at ../Python-3.10.13/Objects/typeobject.c:347
#10 PyType_Modified (type=0xffcd098 <PyBaseObject_Type>) at ../Python-3.10.13/Objects/typeobject.c:316
#11 0x0fce2e74 in type_cache_clear (use_none=<optimized out>, cache=<optimized out>) at ../Python-3.10.13/Objects/typeobject.c:249
#12 _PyType_ClearCache (interp=interp@entry=0x10021df0) at ../Python-3.10.13/Objects/typeobject.c:291
#13 0x0fce2f1c in _PyType_Fini (interp=interp@entry=0x10021df0) at ../Python-3.10.13/Objects/typeobject.c:308
#14 0x0fdbcb94 in finalize_interp_types (interp=0x10021df0) at ../Python-3.10.13/Python/pylifecycle.c:1641
#15 finalize_interp_clear (tstate=tstate@entry=0x10030030) at ../Python-3.10.13/Python/pylifecycle.c:1680
#16 0x0fdc0464 in Py_FinalizeEx () at ../Python-3.10.13/Python/pylifecycle.c:1843
#17 Py_FinalizeEx () at ../Python-3.10.13/Python/pylifecycle.c:1703
#18 0x0fdc146c in Py_Exit (sts=0) at ../Python-3.10.13/Python/pylifecycle.c:2858
#19 0x0fdc791c in handle_system_exit () at ../Python-3.10.13/Python/pythonrun.c:775
#20 _PyErr_PrintEx (tstate=0x10030030, set_sys_last_vars=set_sys_last_vars@entry=1) at ../Python-3.10.13/Python/pythonrun.c:785
#21 0x0fdc7980 in PyErr_PrintEx (set_sys_last_vars=set_sys_last_vars@entry=1) at ../Python-3.10.13/Python/pythonrun.c:880
#22 0x0fdc79a8 in PyErr_Print () at ../Python-3.10.13/Python/pythonrun.c:886
#23 0x0fdc8170 in _PyRun_SimpleFileObject (fp=fp@entry=0x10021430, filename=filename@entry=0xb7c195a0, closeit=closeit@entry=1,
    flags=flags@entry=0xbfbee220) at ../Python-3.10.13/Python/pythonrun.c:462
#24 0x0fdc84f4 in _PyRun_AnyFileObject (fp=fp@entry=0x10021430, filename=filename@entry=0xb7c195a0, closeit=closeit@entry=1,
    flags=flags@entry=0xbfbee220) at ../Python-3.10.13/Python/pythonrun.c:90
#25 0x0fded70c in pymain_run_file_obj (skip_source_first_line=0, filename=0xb7c195a0, program_name=0xb7d04ee0)
    at ../Python-3.10.13/Modules/main.c:353
#26 pymain_run_file (config=0x10021ff4) at ../Python-3.10.13/Modules/main.c:372
#27 pymain_run_python (exitcode=0xbfbee228) at ../Python-3.10.13/Modules/main.c:587
#28 Py_RunMain () at ../Python-3.10.13/Modules/main.c:666
#29 0x0fdedbcc in pymain_main (args=args@entry=0xbfbee2b8) at ../Python-3.10.13/Modules/main.c:696
#30 0x0fdedcb0 in Py_BytesMain (argc=<optimized out>, argv=<optimized out>) at ../Python-3.10.13/Modules/main.c:720
#31 0x10000474 in main (argc=<optimized out>, argv=<optimized out>) at ../Python-3.10.13/Programs/python.c:15

[fduan001]

Anyone know whether op=0x40 is valid or not?

[ZeroIntensity]

Stack traces aren't all that useful here :(

Do you have some code that's causing this? (Especially if you have an extension module active. In that case, it's likely you have an extra DECREF somewhere.)

[vstinner]

Can you reproduce the issue with a debug build of Python?

Moreover, can you try a more recent Python version, such as 3.12, or even 3.13?

op=0x80000000 is a surprising pointer address. op=op@entry=0x40 looks like a null pointer deference.