[Python-Dev] test_subprocess and sparc buildbots

[Georg Brandl]

Alexandre Vassalotti schrieb:
> On Tue, Dec 30, 2008 at 10:41 PM, Daniel (ajax) Diniz <ajaksu at gmail.com> wrote:
>> A reliable way to get that in a --with-pydebug build seems to be:
>>
>> ~/py3k$ ./python -c "import locale; locale.format_string(1,1)"
>> * ob
>> object  : <refcnt 0 at 0x825c76c>
>> type    : tuple
>> refcount: 0
>> address : 0x825c76c
>> * op->_ob_prev->_ob_next
>> NULL
>> * op->_ob_next->_ob_prev
>> object  : <refcnt 0 at 0x825c76c>
>> type    : tuple
>> refcount: 0
>> address : 0x825c76c
>> Fatal Python error: UNREF invalid object
>> TypeError: expected string or buffer
>> Aborted
>>
> 
> Nice catch! I reduced your example to: "import _sre;  _sre.compile(0,
> 0, [])". And, it doesn't seem to be an input validation problem with
> _sre. From what I saw, it's actually a bug in Py_TRACE_REFS's code.
> Now, it's getting interesting!
> 
> It seems something is breaking the refchain. However, I don't know
> what is causing the problem exactly.

This only occurs --with-pydebug, I assume?

It is the same basic problem as in http://bugs.python.org/issue3299,
which I analysed some time ago.  Simply speaking, it is caused by
the object allocation and deallocation scheme that _sre chooses:
if _compile's argument processing raises an error, PyObject_DEL is
called which doesn't remove the object from the refchain.

Georg


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