simple attribute access causing segfault in certain cases

[simon]

BPO	983311
Nosy	@mwhudson, @arigo, @birkenfeld, @zopyx

^{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 2006-01-10.22:00:16.000>
created_at = <Date 2004-07-01.09:42:27.000>
labels = ['interpreter-core']
title = 'simple attribute access causing segfault in certain cases'
updated_at = <Date 2006-01-10.22:00:16.000>
user = 'https://bugs.python.org/simon'

bugs.python.org fields:

activity = <Date 2006-01-10.22:00:16.000>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2004-07-01.09:42:27.000>
creator = 'simon'
dependencies = []
files = []
hgrepos = []
issue_num = 983311
keywords = []
message_count = 10.0
messages = ['21365', '21366', '21367', '21368', '21369', '21370', '21371', '21372', '21373', '21374']
nosy_count = 6.0
nosy_names = ['mwh', 'adustman', 'arigo', 'georg.brandl', 'ajung', 'simon']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue983311'
versions = ['Python 2.3']

[simon]

Reproduce:

 zopectl debug (done in zope debugger to get necessary
imports)
 >>> from AccessControl.tests.testSecurity import
SecurityTests
 >>> SecurityTests.doc_class

Python 2.3.4 crashes silently. Python 2.3.3 works
normally on the same machine. This is some virtual
server variant of debian gnu/linux on intel
(aktiom.net. On another machine (standard debian i386)
Python 2.3.3 shows the same crash.

That attr in
zope/lib/python/AccessControl/tests/testSecurity.py
looks like:

 class SecurityTests (DTMLTests):
     doc_class = UnownedDTML # another class

Cf http://zwiki.org/IssueNo0860 .

[simon]

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Python 2.3.3 works normally on the same machine.

I meant: Python 2.3.3 works normally on another, similar
machine (virtual linux host).

[zopyx]

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Works for me with Python 2.3.3/4 on three different Linux
systems.

[arigo]

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user_id=4771

If this bug involves C extension modules specific to Zope
then I'd first consider it as a bug in one of these modules.
I would be particularly suspicious that this is the case in
a file called testSecurity: isn't its goal to check some
C-implemented security feature of Zope?

If I am wrong please try to provide a Python code sample.
Reading a class attribute out of some class tends to work
just fine.

[simon]

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UnownedDTML is indeed a zope extension class.

[arigo]

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What I mean here is that you should report this bug to Zope, not to Python, unless there is a good reason to suspect that a bug in the Python core is causing it. But to me it really looks like a bug in the Zope extension module, which for some reason shows up only with some version of Python or on some platform.

[simon]

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See also discussion at http://collector.zope.org/Zope/1395

[adustman]

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user_id=71372

This may or may not be related: I've had scattered reports
of people having trouble with attribute access (maybe) with
MySQLdb-1.0.0 on Python-2.3.4 (and maybe 2.3.3 but not 2.2)
on *BSD and Mac OS X, but I can't reproduce it on Linux
(x86) with 2.3.4. One person is getting a segfault upon
import (this is not in the bug listed below); I am trying to
get a gdb backtraces.

https://sourceforge.net/tracker/index.php?func=detail&aid=970667&group_id=22307&atid=374932

[mwhudson]

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user_id=6656

Uh, there seems little chance this is a Python core bug. Can we
close this report?

[birkenfeld]

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I think yes.