Mailing List Archive

New submission from Xinmeng Xia <xiaxm@smail.nju.edu.cn>:

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.

----------
components: Interpreter Core
files: test_code.py
messages: 406740
nosy: xxm
priority: normal
severity: normal
status: open
title: UnboundLocalError leads to Illegal instruction crashing CPython
type: crash
versions: Python 3.11
Added file: https://bugs.python.org/file50455/test_code.py

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Python tracker <report@bugs.python.org>
<https://bugs.python.org/issue45860>
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