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From: Thomas Jollans on 30 Jun 2010 05:56
On 06/30/2010 11:39 AM, Sunil wrote:
> Hi,
>
> We are using a legacy product which is using 1.5.1 version of Python and
> we have seen frequent core dumps offlate which is as below
>
> #0 0x2b79b0 in list_dealloc (op=0x414b11d0) at listobject.c:220
> #1 0x283c48 in dict_dealloc (mp=0x415b8c18) at dictobject.c:491
> #2 0x2b4760 in frame_dealloc (f=0x4042ea50) at frameobject.c:116
> #3 0x28b938 in eval_code2 (co=0x404a4d28, globals=0x4049bec8,
> locals=0x0, args=0x404da5dc, argcount=1, kws=0x0, kwcount=0, defs=0x0,
> defcount=0, owner=0x0)
> at ceval.c:1873
> #4 0x28d690 in call_function (func=0x41497958, arg=0x404da5d0, kw=0x0)
> at ceval.c:2472
>
> Can someone confirm if this is a problem at Python or in the source
> code, I know that this version is quite old and needs upgarde, but since
> this in use for long i would need evidence to prove that this is a
> problem at Python not in the product so that we can upgrade to the
> latest version.
>
> listobject.c
> for (i = 0; i < op->ob_size; i++) {
> Py_XDECREF(op->ob_item[i]); //Line 220
> }
>
> Can some one help me out in this, while i belive that the pointer where
> the derefernece is happening might have got corrupted but this happens
> rarely and the code is a provisioning script with a command that is
> successful most times.

I can't really help much as I've never used Python versions that old.
Some thoughts:

* are you using C extension modules? If you are, double-check their
increfs and decrefs.
* if you're using pure-Python code, the bug is in Python. Python scripts
have no access to memory management and refcounting details (or do
they?) and thus can't currupt anything at that level.
* see http://www.python.org/download/releases/1.6.1/ :
--> What's new in release 1.6.1?
- A core dump in the C API function PyList_Reverse() has been fixed.

possibly relevant?

-- Thomas
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