Running pytest segfaults with Python 3.12 on armhf

[juliangilbey]

This is a very strange one, and might not be the fault of bytecode:

(sid_armhf-dchroot)jdg@abel:~/python-bytecode-0.15.1$ python3.12 -m pytest tests
============================= test session starts ==============================
platform linux -- Python 3.12.1, pytest-7.4.3, pluggy-1.3.0
rootdir: /home/jdg/python-bytecode-0.15.1
configfile: pyproject.toml
collected 165 items                                                            

tests/test_bytecode.py ...s...s......Fatal Python error: Segmentation fault

Current thread 0xb6d47020 (most recent call first):
  File "/usr/lib/python3/dist-packages/bytecode/cfg.py", line 744 in from_bytecode
  File "/usr/lib/python3/dist-packages/bytecode/bytecode.py", line 305 in to_code
  File "/home/jdg/python-bytecode-0.15.1/tests/test_bytecode.py", line 493 in test_negative_size_binary_with_disable_check_of_pre_and_post
  File "/usr/lib/python3.12/unittest/case.py", line 589 in _callTestMethod
  File "/usr/lib/python3.12/unittest/case.py", line 636 in run
  File "/usr/lib/python3.12/unittest/case.py", line 692 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/unittest.py", line 333 in runtest
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 169 in pytest_runtest_call
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 262 in <lambda>
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 341 in from_call
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 261 in call_runtest_hook
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 222 in call_and_report
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 133 in runtestprotocol
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 114 in pytest_runtest_protocol
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 350 in pytest_runtestloop
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 325 in _main
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 271 in wrap_session
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 318 in pytest_cmdline_main
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/config/__init__.py", line 169 in main
  File "/usr/lib/python3/dist-packages/_pytest/config/__init__.py", line 192 in console_main
  File "/usr/lib/python3/dist-packages/pytest/__main__.py", line 5 in <module>
  File "<frozen runpy>", line 88 in _run_code
  File "<frozen runpy>", line 198 in _run_module_as_main
Segmentation fault

It seems to run fine on other architectures, so I don't know what's up here.

[P403n1x87]

a core dump might be helpful if you could get one

[MatthieuDartiailh]

Could you run the other tests by excluding the offending one to see if there are any other tests that trigger a similar behavior ?

[juliangilbey]

Thanks! It seems to be slightly inconsistent which test it crashes at (and occasionally it succeeds on the whole set of tests). (And it consistently succeeds with Python 3.11.) I've attached a core dump with the following Python traceback:

(sid_armhf-dchroot)jdg@abel:~/python-bytecode-0.15.1$ python3.12 -m pytest tests
============================= test session starts ==============================
platform linux -- Python 3.12.1, pytest-7.4.3, pluggy-1.3.0
rootdir: /home/jdg/python-bytecode-0.15.1
configfile: pyproject.toml
collected 165 items                                                            

tests/test_bytecode.py ...s...s..................sss.....                [ 20%]
tests/test_cfg.py ........................Fatal Python error: Segmentation fault

Current thread 0xb6e28020 (most recent call first):
  Garbage-collecting
  File "/usr/lib/python3/dist-packages/bytecode/cfg.py", line 748 in from_bytecode
  File "/usr/lib/python3/dist-packages/bytecode/bytecode.py", line 289 in compute_stacksize
  File "/home/jdg/python-bytecode-0.15.1/tests/test_cfg.py", line 931 in test_huge_code_with_numerous_blocks
  File "/usr/lib/python3.12/unittest/case.py", line 589 in _callTestMethod
  File "/usr/lib/python3.12/unittest/case.py", line 636 in run
  File "/usr/lib/python3.12/unittest/case.py", line 692 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/unittest.py", line 333 in runtest
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 169 in pytest_runtest_call
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 262 in <lambda>
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 341 in from_call
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 261 in call_runtest_hook
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 222 in call_and_report
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 133 in runtestprotocol
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 114 in pytest_runtest_protocol
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 350 in pytest_runtestloop
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 325 in _main
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 271 in wrap_session
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 318 in pytest_cmdline_main
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 77 in _multicall
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 115 in _hookexec
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 493 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/config/__init__.py", line 169 in main
  File "/usr/lib/python3/dist-packages/_pytest/config/__init__.py", line 192 in console_main
  File "/usr/lib/python3/dist-packages/pytest/__main__.py", line 5 in <module>
  File "<frozen runpy>", line 88 in _run_code
  File "<frozen runpy>", line 198 in _run_module_as_main
Segmentation fault (core dumped)

core.gz

[MatthieuDartiailh]

Since I do not have a setup on which to easily open a core dump generated on ARM, could you reproduce the backtrace here ?

[juliangilbey]

Adding a bit more to my previous comment. I've just tried running `python3.12 with debug options:

(sid_armhf-dchroot)jdg@abel:~/python-bytecode-0.15.1$ python3.12 -d -X dev -m pytest tests
============================= test session starts ==============================
platform linux -- Python 3.12.1, pytest-7.4.3, pluggy-1.3.0
rootdir: /home/jdg/python-bytecode-0.15.1
configfile: pyproject.toml
collected 165 items                                                            

tests/test_bytecode.py ...s...s......Aborted (core dumped)

Well, that's not very helpful!

And running gdb on the core dump attached in the previous comment and requesting a backtrace shows the following:

(sid_armhf-dchroot)jdg@abel:~/python-bytecode-0.15.1$ gdb /usr/bin/python3.12 ../core 
[... intro lines snipped ...]
Reading symbols from /usr/bin/python3.12...
Reading symbols from /usr/lib/debug/.build-id/cb/7305157e9d17fb742d979b4a6c90bc2b135e7a.debug...
[New LWP 21180]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".
Core was generated by `python3.12 -m pytest tests'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0xb6e61b06 in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
(gdb) bt
#0  0xb6e61b06 in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
#1  0xb6ea1084 in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
#2  0xb6e70842 in raise () from /lib/arm-linux-gnueabihf/libc.so.6
#3  <signal handler called>
#4  0x000a12e6 in PyType_HasFeature (feature=<optimized out>, 
    type=<optimized out>) at ../Include/object.h:969
#5  _PyObject_IS_GC (obj=<unknown at remote 0xb6060011>)
    at ../Include/internal/pycore_object.h:330
#6  visit_decref (parent=0xb60702e8, op=<unknown at remote 0xb6060011>)
    at ../Modules/gcmodule.c:465
#7  list_traverse (o=0xb60702e8, visit=<optimized out>, arg=0xb60702e8)
    at ../Objects/listobject.c:2705
#8  0x000a122a in subtract_refs (containers=0x54a108 <_PyRuntime+41656>)
    at ../Modules/gcmodule.c:491
#9  deduce_unreachable (base=base@entry=0x54a108 <_PyRuntime+41656>, 
    unreachable=unreachable@entry=0xbe83a648) at ../Modules/gcmodule.c:1116
#10 0x000a0938 in gc_collect_main (
    tstate=tstate@entry=0x5796d0 <_PyRuntime+235648>, 
    generation=generation@entry=2, n_collected=n_collected@entry=0xbe83a6ec, 
    n_uncollectable=n_uncollectable@entry=0xbe83a6e8, nofail=<optimized out>, 
    nofail@entry=0) at ../Modules/gcmodule.c:1242
#11 0x00160a80 in gc_collect_with_callback (
    tstate=0x5796d0 <_PyRuntime+235648>, generation=2)
    at ../Modules/gcmodule.c:1426
#12 0x00160a2c in gc_collect_generations.isra.0 (
    tstate=tstate@entry=0x5796d0 <_PyRuntime+235648>)
    at ../Modules/gcmodule.c:1481
#13 0x0009a5c6 in _Py_RunGC (tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Modules/gcmodule.c:2292
#14 _Py_HandlePending (tstate=<optimized out>) at ../Python/ceval_gil.c:1045
#15 _PyEval_EvalFrameDefault (tstate=<optimized out>, frame=<optimized out>, 
    throwflag=<optimized out>) at ../Python/ceval.c:834
#16 0x000e6318 in _PyEval_EvalFrame (throwflag=0, frame=0xb6d45ac4, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_ceval.h:89
#17 _PyEval_Vector (kwnames=('result',), argcount=1, args=0xb6d5d670, 
    locals=0x0, func=0xb66ec758, tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Python/ceval.c:1683
#18 _PyFunction_Vectorcall (kwnames=('result',), nargsf=<optimized out>, 
    stack=0xb6d5d670, func=<function at remote 0xb66ec758>)
    at ../Objects/call.c:419
#19 _PyObject_VectorcallTstate (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb66ec758>, args=0xb6d5d670, 
    nargsf=<optimized out>, kwnames=<optimized out>)
    at ../Include/internal/pycore_call.h:92
#20 0x000e60f4 in method_vectorcall (method=<optimized out>, args=0xb6d5d674, 
    nargsf=<optimized out>, kwnames=('result',)) at ../Objects/classobject.c:61
#21 0x000c9194 in _PyVectorcall_Call (kwargs=<optimized out>, 
    tuple=<optimized out>, callable=<method at remote 0xb5fc77c8>, 
    func=0xe6061 <method_vectorcall>, tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Objects/call.c:283
#22 _PyObject_Call (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<method at remote 0xb5fc77c8>, args=<optimized out>, 
    kwargs=<optimized out>) at ../Objects/call.c:354
#23 0x000950a6 in PyCFunction_Call (
    kwargs={'result': <TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one of the possible fixture scopes in pytest.\n\n    Scopes are ordered from lower to higher, that is:\n\n              ->>> hig...(truncated), args=(), callable=<method at remote 0xb5fc77c8>)
    at ../Objects/call.c:387
#24 _PyEval_EvalFrameDefault (tstate=<optimized out>, frame=<optimized out>, 
    throwflag=<optimized out>) at Python/bytecodes.c:3254
#25 0x00088f4a in _PyObject_FastCallDictTstate (
    tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb66ec848>, args=0xbe83a98c, 
    nargsf=<optimized out>, kwargs=<optimized out>) at ../Objects/call.c:144
#26 0x000c64cc in _PyObject_Call_Prepend (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb66ec848>, 
    obj=<CFGStacksizeComputationTests(_testMethodName='test_huge_code_with_numerous_blocks', _outcome=<_Outcome(expecting_failure=False, result=<TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one...(truncated), args=<optimized out>, kwargs=<optimized out>) at ../Objects/call.c:508
#27 0x001acd84 in slot_tp_call (
    self=<CFGStacksizeComputationTests(_testMethodName='test_huge_code_with_numerous_blocks', _outcome=<_Outcome(expecting_failure=False, result=<TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one...(truncated), args=(), 
    kwds={'result': <TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one of the possible fixture scopes in pytest.\n\n    Scopes are ordered from lower to higher, that is:\n\n              ->>> hig...(truncated)) at ../Objects/typeobject.c:8769
#28 0x00083394 in _PyObject_MakeTpCall (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<CFGStacksizeComputationTests(_testMethodName='test_huge_code_with_numerous_blocks', _outcome=<_Outcome(expecting_failure=False, result=<TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one...(truncated), args=<optimized out>, nargs=0, keywords=('result',))
    at ../Objects/call.c:240
#29 0x000a8980 in _PyObject_VectorcallTstate (kwnames=('result',), 
    nargsf=<optimized out>, args=<optimized out>, 
    callable=<CFGStacksizeComputationTests(_testMethodName='test_huge_code_with_numerous_blocks', _outcome=<_Outcome(expecting_failure=False, result=<TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one...(truncated), tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:90
#30 _PyObject_VectorcallTstate (kwnames=('result',), nargsf=<optimized out>, 
    args=<optimized out>, 
    callable=<CFGStacksizeComputationTests(_testMethodName='test_huge_code_with_numerous_blocks', _outcome=<_Outcome(expecting_failure=False, result=<TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one...(truncated), tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:77
#31 PyObject_Vectorcall (
    callable=<CFGStacksizeComputationTests(_testMethodName='test_huge_code_with_numerous_blocks', _outcome=<_Outcome(expecting_failure=False, result=<TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one...(truncated), args=<optimized out>, nargsf=<optimized out>, kwnames=('result',))
    at ../Objects/call.c:325
#32 0x00092334 in _PyEval_EvalFrameDefault (tstate=<optimized out>, 
    frame=<optimized out>, throwflag=<optimized out>)
    at Python/bytecodes.c:2706
#33 0x00088f4a in _PyObject_FastCallDictTstate (
    tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, args=0xbe83ab4c, 
    nargsf=<optimized out>, kwargs=<optimized out>) at ../Objects/call.c:144
#34 0x000c64cc in _PyObject_Call_Prepend (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, 
    obj=<HookCaller at remote 0xb6627bb8>, args=<optimized out>, 
    kwargs=<optimized out>) at ../Objects/call.c:508
#35 0x001acd84 in slot_tp_call (self=<HookCaller at remote 0xb6627bb8>, 
    args=(), 
    kwds={'item': <TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one of the possible fixture scopes in pytest.\n\n    Scopes are ordered from lower to higher, that is:\n\n              ->>> highe...(truncated)) at ../Objects/typeobject.c:8769
#36 0x000c913a in _PyObject_Call (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<HookCaller at remote 0xb6627bb8>, args=(), 
    kwargs=<optimized out>) at ../Objects/call.c:367
#37 0x000950a6 in PyCFunction_Call (
    kwargs={'item': <TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one of the possible fixture scopes in pytest.\n\n    Scopes are ordered from lower to higher, that is:\n\n              ->>> highe...(truncated), args=(), callable=<HookCaller at remote 0xb6627bb8>)
    at ../Objects/call.c:387
#38 _PyEval_EvalFrameDefault (tstate=<optimized out>, frame=<optimized out>, 
    throwflag=<optimized out>) at Python/bytecodes.c:3254
#39 0x00088f4a in _PyObject_FastCallDictTstate (
    tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, args=0xbe83acf4, 
    nargsf=<optimized out>, kwargs=<optimized out>) at ../Objects/call.c:144
#40 0x000c64cc in _PyObject_Call_Prepend (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, 
    obj=<HookCaller at remote 0xb6627de8>, args=<optimized out>, 
    kwargs=<optimized out>) at ../Objects/call.c:508
#41 0x001acd84 in slot_tp_call (self=<HookCaller at remote 0xb6627de8>, 
    args=(), 
    kwds={'item': <TestCaseFunction(keywords=<NodeKeywords at remote 0xb60b31e8>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb60a9eb0>, _report_sections=[], user_properties=[], _obj=<method at remote 0xb5fc7228>, originalname='test_huge_code_with_numerous_blocks', _fixtureinfo=<FuncFixtureInfo at remote 0xb60b3268>, fixturenames=['_unittest_setUpClass_fixture_CFGStacksizeComputationTests', 'request'], funcargs={'_unittest_setUpClass_fixture_CFGStacksizeComputationTests': None, 'request': <FixtureRequest(_pyfuncitem=<...>, fixturename=None, _scope=<Scope(_value_='function', _name_='Function', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb679bfa0>, __module__='_pytest.scope', __annotations__={'Function': '_ScopeName', 'Class': '_ScopeName', 'Module': '_ScopeName', 'Package': '_ScopeName', 'Session': '_ScopeName'}, __doc__='\n    Represents one of the possible fixture scopes in pytest.\n\n    Scopes are ordered from lower to higher, that is:\n\n              ->>> highe...(truncated)) at ../Objects/typeobject.c:8769
#42 0x00083394 in _PyObject_MakeTpCall (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<HookCaller at remote 0xb6627de8>, args=<optimized out>, nargs=0, 
    keywords=('item', 'nextitem')) at ../Objects/call.c:240
#43 0x000a8980 in _PyObject_VectorcallTstate (kwnames=('item', 'nextitem'), 
    nargsf=<optimized out>, args=<optimized out>, 
    callable=<HookCaller at remote 0xb6627de8>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:90
#44 _PyObject_VectorcallTstate (kwnames=('item', 'nextitem'), 
    nargsf=<optimized out>, args=<optimized out>, 
    callable=<HookCaller at remote 0xb6627de8>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:77
#45 PyObject_Vectorcall (callable=<HookCaller at remote 0xb6627de8>, 
    args=<optimized out>, nargsf=<optimized out>, kwnames=('item', 'nextitem'))
    at ../Objects/call.c:325
#46 0x00092334 in _PyEval_EvalFrameDefault (tstate=<optimized out>, 
    frame=<optimized out>, throwflag=<optimized out>)
    at Python/bytecodes.c:2706
#47 0x00088f4a in _PyObject_FastCallDictTstate (
    tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, args=0xbe83aeb4, 
    nargsf=<optimized out>, kwargs=<optimized out>) at ../Objects/call.c:144
#48 0x000c64cc in _PyObject_Call_Prepend (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, 
    obj=<HookCaller at remote 0xb6627f00>, args=<optimized out>, 
    kwargs=<optimized out>) at ../Objects/call.c:508
#49 0x001acd84 in slot_tp_call (self=<HookCaller at remote 0xb6627f00>, 
    args=(), 
    kwds={'session': <Session(keywords=<NodeKeywords at remote 0xb658eb08>, own_markers=[], extra_keyword_matches=set(), stash=<Stash at remote 0xb6621d78>, testsfailed=0, testscollected=165, shouldstop=False, shouldfail=False, trace=<TagTracerSub(root=<TagTracer(_tags2proc={}, _writer=None, indent=0) at remote 0xb6d86e58>, tags=('collection',)) at remote 0xb66214b0>, _initialpaths=frozenset({<PosixPath at remote 0xb655b840>}), _bestrelpathcache=<_bestrelpath_cache at remote 0xb67a2028>, exitstatus=<ExitCode(_value_=0, _name_='OK', __objclass__=<EnumType(_generate_next_value_=<staticmethod at remote 0xb68503e8>, __module__='_pytest.config', __doc__='Encodes the valid exit codes by pytest.\n\n    Currently users and plugins may supply other exit codes as well.\n\n    .. versionadded:: 5.0\n    ', _new_member_=<built-in method __new__ of type object at remote 0x4a2554>, _use_args_=True, _member_names_=['OK', 'TESTS_FAILED', 'INTERRUPTED', 'INTERNAL_ERROR', 'USAGE_ERROR', 'NO_TESTS_COLLECTED'], _member_map_={'OK': <...>,...(truncated)) at ../Objects/typeobject.c:8769
#50 0x00083394 in _PyObject_MakeTpCall (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<HookCaller at remote 0xb6627f00>, args=<optimized out>, nargs=0, 
    keywords=('session',)) at ../Objects/call.c:240
#51 0x000a8980 in _PyObject_VectorcallTstate (kwnames=('session',), 
    nargsf=<optimized out>, args=<optimized out>, 
    callable=<HookCaller at remote 0xb6627f00>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:90
#52 _PyObject_VectorcallTstate (kwnames=('session',), nargsf=<optimized out>, 
    args=<optimized out>, callable=<HookCaller at remote 0xb6627f00>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:77
#53 PyObject_Vectorcall (callable=<HookCaller at remote 0xb6627f00>, 
    args=<optimized out>, nargsf=<optimized out>, kwnames=('session',))
    at ../Objects/call.c:325
#54 0x00092334 in _PyEval_EvalFrameDefault (tstate=<optimized out>, 
    frame=<optimized out>, throwflag=<optimized out>)
    at Python/bytecodes.c:2706
#55 0x00088f4a in _PyObject_FastCallDictTstate (
    tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, args=0xbe83b074, 
    nargsf=<optimized out>, kwargs=<optimized out>) at ../Objects/call.c:144
#56 0x000c64cc in _PyObject_Call_Prepend (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<function at remote 0xb69307f8>, 
    obj=<HookCaller at remote 0xb661fd98>, args=<optimized out>, 
    kwargs=<optimized out>) at ../Objects/call.c:508
#57 0x001acd84 in slot_tp_call (self=<HookCaller at remote 0xb661fd98>, 
    args=(), 
    kwds={'config': <Config(option=<Namespace(keyword='', markexpr='', maxfail=0, continue_on_collection_errors=False, confcutdir=None, noconftest=False, keepduplicates=False, collect_in_virtualenv=False, importmode='prepend', basetemp=None, durations=None, durations_min=<float at remote 0xb6936290>, version=0, plugins=[], traceconfig=False, showfixtures=False, show_fixtures_per_test=False, verbose=0, no_header=False, no_summary=False, reportchars='fE', disable_warnings=False, showlocals=False, tbstyle='auto', showcapture='all', fulltrace=False, color='auto', code_highlight='yes', capture='fd', runxfail=False, pastebin=None, assertmode='rewrite', xmlpath=None, junitprefix=None, doctestmodules=False, doctestreport='udiff', doctestglob=[], doctest_ignore_import_errors=False, doctest_continue_on_failure=False, last_failed_no_failures='all', stepwise=False, stepwise_skip=False, logger_disable=[], markers=False, usepdb=False, usepdb_cls=None, trace=False, lf=False, failedfirst=False, newfirst=False, cacheshow=None, cachecl...(truncated)) at ../Objects/typeobject.c:8769
#58 0x00083394 in _PyObject_MakeTpCall (tstate=0x5796d0 <_PyRuntime+235648>, 
    callable=<HookCaller at remote 0xb661fd98>, args=<optimized out>, nargs=0, 
    keywords=('config',)) at ../Objects/call.c:240
#59 0x000a8980 in _PyObject_VectorcallTstate (kwnames=('config',), 
    nargsf=<optimized out>, args=<optimized out>, 
    callable=<HookCaller at remote 0xb661fd98>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:90
#60 _PyObject_VectorcallTstate (kwnames=('config',), nargsf=<optimized out>, 
    args=<optimized out>, callable=<HookCaller at remote 0xb661fd98>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:77
#61 PyObject_Vectorcall (callable=<HookCaller at remote 0xb661fd98>, 
    args=<optimized out>, nargsf=<optimized out>, kwnames=('config',))
    at ../Objects/call.c:325
#62 0x00092334 in _PyEval_EvalFrameDefault (tstate=<optimized out>, 
    frame=<optimized out>, throwflag=<optimized out>)
    at Python/bytecodes.c:2706
#63 0x0015fda6 in _PyEval_EvalFrame (throwflag=0, frame=0xb6d450e4, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_ceval.h:89
#64 _PyEval_Vector (args=0x0, argcount=0, kwnames=0x0, locals=<optimized out>, 
    func=0xb6d5ae88, tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Python/ceval.c:1683
#65 PyEval_EvalCode (co=<optimized out>, globals=<optimized out>, 
    locals=<optimized out>) at ../Python/ceval.c:578
#66 0x00176828 in builtin_exec_impl (module=<optimized out>, 
    closure=<optimized out>, 
    locals={'__name__': '__main__', '__doc__': 'The pytest entry point.', '__package__': 'pytest', '__loader__': <SourceFileLoader(name='pytest.__main__', path='/usr/lib/python3/dist-packages/pytest/__main__.py') at remote 0xb670d348>, '__spec__': <ModuleSpec(name='pytest.__main__', loader=<...>, origin='/usr/lib/python3/dist-packages/pytest/__main__.py', loader_state=None, submodule_search_locations=None, _uninitialized_submodules=[], _set_fileattr=True, _cached='/usr/lib/python3/dist-packages/pytest/__pycache__/__main__.cpython-312.pyc') at remote 0xb6cc66a8>, '__annotations__': {}, '__builtins__': <module at remote 0xb6d53398>, '__file__': '/usr/lib/python3/dist-packages/pytest/__main__.py', '__cached__': '/usr/lib/python3/dist-packages/pytest/__pycache__/__main__.cpython-312.pyc', 'pytest': <module at remote 0xb6d408c0>}, 
    globals={'__name__': '__main__', '__doc__': 'The pytest entry point.', '__package__': 'pytest', '__loader__': <SourceFileLoader(name='pytest.__main__', path='/usr/lib/python3/dist-packages/pytest/__main__.py') at remote 0xb670d348>, '__spec__': <ModuleSpec(name='pytest.__main__', loader=<...>, origin='/usr/lib/python3/dist-packages/pytest/__main__.py', loader_state=None, submodule_search_locations=None, _uninitialized_submodules=[], _set_fileattr=True, _cached='/usr/lib/python3/dist-packages/pytest/__pycache__/__main__.cpython-312.pyc') at remote 0xb6cc66a8>, '__annotations__': {}, '__builtins__': <module at remote 0xb6d53398>, '__file__': '/usr/lib/python3/dist-packages/pytest/__main__.py', '__cached__': '/usr/lib/python3/dist-packages/pytest/__pycache__/__main__.cpython-312.pyc', 'pytest': <module at remote 0xb6d408c0>}, source=<code at remote 0xb662ea48>)
    at ../Python/bltinmodule.c:1096
#67 builtin_exec (module=<optimized out>, args=<optimized out>, 
    nargs=<optimized out>, kwnames=<optimized out>)
    at ../Python/clinic/bltinmodule.c.h:586
#68 0x000a8b48 in cfunction_vectorcall_FASTCALL_KEYWORDS (
    func=<built-in method exec of module object at remote 0xb6d53398>, 
    args=0xb6d450c8, nargsf=<optimized out>, kwnames=<optimized out>)
    at ../Objects/methodobject.c:438
#69 0x000a895e in _PyObject_VectorcallTstate (kwnames=0x0, 
    nargsf=<optimized out>, args=<optimized out>, 
    callable=<built-in method exec of module object at remote 0xb6d53398>, 
    tstate=0x5796d0 <_PyRuntime+235648>)
    at ../Include/internal/pycore_call.h:92
#70 PyObject_Vectorcall (
    callable=<built-in method exec of module object at remote 0xb6d53398>, 
    args=<optimized out>, nargsf=<optimized out>, kwnames=0x0)
    at ../Objects/call.c:325
#71 0x00092334 in _PyEval_EvalFrameDefault (tstate=<optimized out>, 
    frame=<optimized out>, throwflag=<optimized out>)
    at Python/bytecodes.c:2706
#72 0x0018ae02 in pymain_run_module (modname=<optimized out>, set_argv0=1)
    at ../Modules/main.c:300
#73 0x0018a38c in pymain_run_python (exitcode=0xbe83b3c0)
    at ../Modules/main.c:623
#74 Py_RunMain () at ../Modules/main.c:709
#75 0x0014ea00 in Py_BytesMain (argc=4, argv=<optimized out>)
    at ../Modules/main.c:763
#76 0xb6e617da in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
#77 0xb6e6187e in __libc_start_main () from /lib/arm-linux-gnueabihf/libc.so.6
#78 0x0014e8e4 in _start ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) 

I don't know much at all about Python's internals, but my limited understanding from this backtrace is that it's crashed inside the garbage collector (#10), though I may be completely wrong about this.

[P403n1x87]

To me the most obvious cause is a potential CPython frame stack corruption (e.g. a missing RESUME or other prefix instructions etc...). Tests crashing only with CPython >= 3.11 might be an indication of this.

[juliangilbey]

I tried running with the failing test excluded:

(sid_armhf-dchroot)jdg@abel:~/python-bytecode-0.15.1$ python3.12 -m pytest tests -k "not test_huge_code_with_numerous_blocks"
============================= test session starts ==============================
platform linux -- Python 3.12.1, pytest-7.4.3, pluggy-1.3.0
rootdir: /home/jdg/python-bytecode-0.15.1
configfile: pyproject.toml
collected 165 items / 1 deselected / 164 selected                              

tests/test_bytecode.py ...s...s..................sss.....                [ 20%]
tests/test_cfg.py .........................................              [ 45%]
tests/test_code.py ......                                                [ 49%]
tests/test_concrete.py ......................s.......s........Fatal Python error: Segmentation fault

Current thread 0xb6da4020 (most recent call first):
  Garbage-collecting
  File "/usr/lib/python3/dist-packages/bytecode/instr.py", line 528 in __init__
  File "/usr/lib/python3/dist-packages/bytecode/concrete.py", line 1068 in to_bytecode
  File "/usr/lib/python3/dist-packages/bytecode/concrete.py", line 862 in to_code
  File "/home/jdg/python-bytecode-0.15.1/tests/test_concrete.py", line 1514 in test_extended_jump
  File "/usr/lib/python3.12/unittest/case.py", line 589 in _callTestMethod
  [...]

Trying to exclude both of these tests was even less informative:

(sid_armhf-dchroot)jdg@abel:~/python-bytecode-0.15.1$ python3.12 -m pytest tests -k "not test_huge_code_with_numerous_blocks and not test_extended_jump"
============================= test session starts ==============================
platform linux -- Python 3.12.1, pytest-7.4.3, pluggy-1.3.0
rootdir: /home/jdg/python-bytecode-0.15.1
configfile: pyproject.toml
collected 165 items / 2 deselected / 163 selected                              

tests/test_bytecode.py ...s...s..................sss.....                [ 20%]
tests/test_cfg.py .........................................              [ 46%]
tests/test_code.py ......                                                [ 49%]
tests/test_concrete.py ......................s.......s...............    [ 77%]
tests/test_flags.py ..ss..                                               [ 81%]
tests/test_instr.py ........................                             [ 96%]
tests/test_misc.py ......                                                [100%]

================ 154 passed, 9 skipped, 2 deselected in 17.94s =================
Segmentation fault

Looking at the core dump in this last case, which is very short, it again fails in the garbage collection:

Core was generated by `python3.12 -m pytest tests -k not test_huge_code_with_numerous_blocks and not t'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x000a12e6 in PyType_HasFeature (feature=<optimized out>, 
    type=<optimized out>) at ../Include/object.h:969
969	../Include/object.h: No such file or directory.
(gdb) bt
#0  0x000a12e6 in PyType_HasFeature (feature=<optimized out>, 
    type=<optimized out>) at ../Include/object.h:969
#1  _PyObject_IS_GC (obj=<unknown at remote 0xb6060011>)
    at ../Include/internal/pycore_object.h:330
#2  visit_decref (parent=0xb60633a8, op=<unknown at remote 0xb6060011>)
    at ../Modules/gcmodule.c:465
#3  list_traverse (o=0xb60633a8, visit=<optimized out>, arg=0xb60633a8)
    at ../Objects/listobject.c:2705
#4  0x000a122a in subtract_refs (containers=0x54a108 <_PyRuntime+41656>)
    at ../Modules/gcmodule.c:491
#5  deduce_unreachable (base=base@entry=0x54a108 <_PyRuntime+41656>, 
    unreachable=unreachable@entry=0xbeabd250) at ../Modules/gcmodule.c:1116
#6  0x000a0938 in gc_collect_main (
    tstate=tstate@entry=0x5796d0 <_PyRuntime+235648>, 
    generation=generation@entry=2, n_collected=n_collected@entry=0xbeabd2f4, 
    n_uncollectable=n_uncollectable@entry=0xbeabd2f0, nofail=<optimized out>, 
    nofail@entry=0) at ../Modules/gcmodule.c:1242
#7  0x00160a80 in gc_collect_with_callback (
    tstate=0x5796d0 <_PyRuntime+235648>, generation=2)
    at ../Modules/gcmodule.c:1426
#8  0x001924f4 in PyGC_Collect () at ../Modules/gcmodule.c:2111
#9  0x0017b93c in Py_FinalizeEx () at ../Python/pylifecycle.c:1885
#10 0x0018a3ce in Py_RunMain () at ../Modules/main.c:711
#11 0x0014ea00 in Py_BytesMain (argc=6, argv=<optimized out>)
    at ../Modules/main.c:763
#12 0xb6e517da in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
#13 0xb6e5187e in __libc_start_main () from /lib/arm-linux-gnueabihf/libc.so.6
#14 0x0014e8e4 in _start ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

It seems fine with Python 3.11, though, so there is some change in Python 3.12 which is causing this corruption. But what I don't know is whether it is a bytecode issue or, as is seeming more likely now, a Python 3.12 issue.

[P403n1x87]

Backtrace stopped: previous frame identical to this frame (corrupt stack?)

This seems to be another cue for frame stack corruption. I've had these in the past with bad bytecode from my side, so that's why I think this could be due to some inaccurate bytecode reconstruction in at least one of the tests. What I find strange is how this is not being caught by the framework test 🤔

[juliangilbey]

Backtrace stopped: previous frame identical to this frame (corrupt stack?)

This seems to be another cue for frame stack corruption. I've had these in the past with bad bytecode from my side, so that's why I think this could be due to some inaccurate bytecode reconstruction in at least one of the tests. What I find strange is how this is not being caught by the framework test 🤔

It's also weird that of all the architectures it's being tested on (I'm not sure exactly which yet), I've only received a report that it fails on armhf. It certainly succeeds on amd64. If you'd like me to test it on other architectures, I could.

[MatthieuDartiailh]

I am honestly not sure what is going on here. To make sure bytecode is really in cause, could you pick one offending test and disable any recompiled bytecode execution and see if the error persist ? You can use pytest-repeat to easily run multiple times the same test.
Anotrher thing you could attempt is to create an auto-use fixture running the GC manually to see if it makes the failure more consistent.

[juliangilbey]

Hi @MatthieuDartiailh, thanks for taking a look at this!

I'm not sure I fully understand your request, I'm afraid, but I'll give it my best shot. Here is what I've tried; the results are weird, but perhaps this is informative? To ensure I've not missed anything, I've patched up to the most recent commit: f586bae

I was consistently finding that it crashed, reporting that it was in test_cfg.py::test_huge_code_with_numerous_blocks. So I modified the final lines of the test:

        bytecode = Bytecode(mk_if_then_else(5000))                            
        bytecode.compute_stacksize()                                          

in three ways:

1. I commented out the bytecode.compute_stacksize() call. The test still crashed at the same place.
2. I replaced the Bytecode call by instructs = mk_if_then_else(5000) (and still commented out the final line). The test still crashed at the same place.
3. I commented out both of these lines and replaced them with a simple pass. The test now passed, and the crash occurred at test_roundtrip_exception_handling.

Next, I tried creating an autouse fixture:

# contents of tests/conftest.py
import gc

import pytest

@pytest.fixture(autouse=True)
def run_gc():
    yield
    gc.collect()

and now running pytest with Python 3.12 consistently crashes at tests/test_bytecode.py::test_negative_size_binary_with_disable_check_of_pre_and_post. So I commented out the final two lines of that test (the lines co = code.to_code(...) and self.assertEqual(...)) and now everything runs without trouble.

I then removed conftest.py, leaving the test_negative_size_binary_with_disable_check_of_pre_and_post test disabled, and the pytest run still runs smoothly. So it looks as though this may be the source of the issue, though I have nowhere near enough understanding to know why.

Finally, I left the test unpatched and ran pytest with the option --deselect=tests/test_bytecode.py::test_negative_size_binary_with_disable_check_of_pre_and_post. But then it crashed at test_huge_code_with_numerous_blocks once again, which is just weird.