classification
Title: UnboundLocalError leads to Illegal instruction crashing CPython
Type: crash Stage:
Components: Interpreter Core Versions: Python 3.11
process
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: lukasz.langa, xxm
Priority: normal Keywords:

Created on 2021-11-22 02:24 by xxm, last changed 2021-11-27 00:10 by terry.reedy.

Files
File name Uploaded Description Edit
test_code.py xxm, 2021-11-22 02:24
Messages (1)
msg406740 - (view) Author: Xinmeng Xia (xxm) Date: 2021-11-22 02:24
The following code can lead to a crash and report Illegal instruction (core dumped)(few times) or Trace/breakpoint trap (core dumped) (very few times) or Segmentation fault (core dumped) (most times) on Python 3.11. 

test_free_different_thread.py
========================================================
import inspect
import sys
import threading
import unittest
import weakref
import ctypes
from test.support import run_doctest, run_unittest, cpython_only, check_impl_detail
import _testcapi
from types import FunctionType
from test import test_code
import test_code

def test_free_different_thread():
    f = CoExtra.get_func()

    class ThreadTest(threading.Thread):

        def __init__(CoExtra, f, test):
            super().__init__()
            CoExtra.f = CoExtra
            CoExtra.test = test

        def run(CoExtra):
            del CoExtra.f
            CoExtra.test.assertEqual(test_code.LAST_FREED, 500)
    test_code.SetExtra(f.__code__, test_code.FREE_INDEX, ctypes.c_voidp(500))
    f = ThreadTest(CoExtra, f)
    del tt
    tt.start()
    tt.join()
    CoExtra.assertEqual(test_code.LAST_FREED, 500)
    
CoExtra = test_code.CoExtra()
test_free_different_thread()
=========================================================

-------------------------------------
Traceback (most recent call last):
  File "/home/xxm/Desktop/test_free_different_thread.py", line 33, in <module>
    test_free_different_thread()
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/xxm/Desktop/test_free_different_thread.py", line 28, in test_free_different_thread
    del tt
        ^^
UnboundLocalError: cannot access local variable 'tt' where it is not associated with a value
Illegal instruction (core dumped)/Trace/breakpoint trap (core dumped)/Segmentation fault (core dumped)
----------------------------------------------------------------

Version: python 3.9, python 3.10, python 3.11 on ubuntu 16.04

Reproduce step:
1.download test_code.py and place test_free_different_thread.py and test_code in a same directory.
2. run with "python test_free_different_thread.py"

The test_code.py is from cpython' test. We can also annotate "import test_code" and run test_free_different_thread.py directly. But it seems that Illegal instruction and Trace/breakpoint trap cannot be reproduced.
History
Date User Action Args
2021-11-27 00:10:58terry.reedysetnosy: + lukasz.langa
2021-11-22 02:24:42xxmcreate