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Weakref proxy crashes on null tp_iternext slot. #88883

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xxm mannequin opened this issue Jul 23, 2021 · 6 comments
Closed

Weakref proxy crashes on null tp_iternext slot. #88883

xxm mannequin opened this issue Jul 23, 2021 · 6 comments
Labels
3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes 3.10 only security fixes 3.11 only security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) type-crash A hard crash of the interpreter, possibly with a core dump

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@xxm
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xxm mannequin commented Jul 23, 2021

BPO 44720
Nosy @ambv, @miss-islington, @sweeneyde
PRs
  • bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ #27316
  • [3.10] bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ (GH-27316) #27324
  • [3.9] bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ (GH-27316) #27325
    		•
    Files
  • test.py
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
closed_at = <Date 2021-07-24.09:46:50.166>
created_at = <Date 2021-07-23.05:05:41.949>
labels = ['interpreter-core', '3.8', '3.9', '3.10', '3.11', '3.7', 'type-crash']
title = 'Weakref proxy crashes on null tp_iternext slot.'
updated_at = <Date 2021-07-24.09:46:50.165>
user = 'https://bugs.python.org/xxm'

    bugs.python.org fields:

    activity = <Date 2021-07-24.09:46:50.165>
actor = 'lukasz.langa'
assignee = 'none'
closed = True
closed_date = <Date 2021-07-24.09:46:50.166>
closer = 'lukasz.langa'
components = ['Interpreter Core']
creation = <Date 2021-07-23.05:05:41.949>
creator = 'xxm'
dependencies = []
files = ['50171']
hgrepos = []
issue_num = 44720
keywords = ['patch']
message_count = 6.0
messages = ['398029', '398114', '398127', '398131', '398132', '398133']
nosy_count = 4.0
nosy_names = ['lukasz.langa', 'miss-islington', 'Dennis Sweeney', 'xxm']
pr_nums = ['27316', '27324', '27325']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue44720'
versions = ['Python 3.6', 'Python 3.7', 'Python 3.8', 'Python 3.9', 'Python 3.10', 'Python 3.11']
    @xxm
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    xxm mannequin commented Jul 23, 2021

    This piece of code is originally from https://github.com/python/cpython/tree/main/Lib/test/test_weakref.py. In function test_proxy_iter(), we change the original data dependency and then this generated test case (see the following "test.py") crashes Python.

    Crashing Python version: 3.6-master(3.11.0a0)

    test.py
    =========================

    import weakref


def test_proxy_iter():
    obj = None

    class MyObj:
            def __iter__(a):
            nonlocal obj
            del obj
-           return NotImplemented
+           return p
    obj = MyObj()
-   p = weakref.proxy(obj)
+   p = weakref.proxy(TypeError)
    • 'blech' in p
      + 'blech' in obj
    test_proxy_iter()

    ===========================

    system: ubuntu 16.04
    crash: segmentation fault

    @xxm xxm mannequin added 3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes 3.10 only security fixes 3.11 only security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) type-crash A hard crash of the interpreter, possibly with a core dump labels Jul 23, 2021
    @sweeneyde
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    Here's a simpler reproducer:

            not_an_iterator = lambda: 0

        class A:
            def __iter__(self):
                return weakref.proxy(not_an_iterator)
        a = A()
        list(a)

    I opened a PR.

    @sweeneyde sweeneyde changed the title Finding string in iteratively deleted object cause segfault Weakref proxy crashes on null tp_iternext slot. Jul 24, 2021
    @ambv
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    ambv commented Jul 24, 2021

    New changeset 5370f0a by Dennis Sweeney in branch 'main':
    bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ (GH-27316)
    5370f0a

    @ambv
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    ambv commented Jul 24, 2021

    New changeset 659030c by Miss Islington (bot) in branch '3.10':
    bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ (GH-27316) (GH-27324)
    659030c

    @ambv
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    ambv commented Jul 24, 2021

    New changeset 0a08f22 by Miss Islington (bot) in branch '3.9':
    bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ (GH-27316) (bpo-27325)
    0a08f22

    @ambv
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    ambv commented Jul 24, 2021

    Thanks for your quick pull request, Dennis! ✨ 🍰 ✨

    @ambv ambv closed this as completed Jul 24, 2021
    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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