[Python-bugs-list] [ python-Bugs-528132 ] classmethod().__get__() segfault

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Bugs item #528132, was opened at 2002-03-10 10:19
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Category: Type/class unification
Group: Python 2.2.1 candidate
Status: Open
Resolution: None
Priority: 7
Submitted By: Armin Rigo (arigo)
Assigned to: Guido van Rossum (gvanrossum)
Summary: classmethod().__get__() segfault

Initial Comment:
Calling the __get__ method of a classmethod object 
with a single argument causes a segmentation fault in 
the interpreter :

  def f(): pass
  classmethod(f).__get__(0)

This is caused by an internal inconsistency between 
the __get__ wrapper function in C that calls the 
tp_descr_get slot with a NULL third argument in this 
case and some tp_descr_get slot implementations (like 
the classmethods') which dereference it with no check.

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>Comment By: Guido van Rossum (gvanrossum)
Date: 2002-03-17 18:08

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Alas, not tonight. Tomorrow morning for sure.

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Comment By: Guido van Rossum (gvanrossum)
Date: 2002-03-17 17:10

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Alas, it looks I can still force a segfault by calling the
resulting unbound method with a bogus argument. I'll look
into this now.

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Comment By: Michael Hudson (mwh)
Date: 2002-03-17 15:11

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Guido, is this fix sane?

No other implementation of tp_descr_get seems to be at risk.

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Comment By: Michael Hudson (mwh)
Date: 2002-03-16 12:37

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Oopsie, we'll have this one fixed for 2.2.1.

I think you mangaged to submit this bug during a time when
bug email was somewhat hosed...

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