Re: Segfault in PL/Python

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Segfault in PL/Python
Date: 2009-11-03 10:36:47
Message-ID: 1257244607.25627.0.camel@fsopti579.F-Secure.com
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On Sat, 2009-10-31 at 14:24 +0200, Peter Eisentraut wrote:
> I have discovered an obscure segfault condition in PL/Python. In
> PLy_output(), when the elog() call in the TRY branch throws an exception
> (this can happen when a statement timeout kicks in, for example), the
> PyErr_SetString() call in the CATCH branch can cause a segfault, because
> the Py_XDECREF(so) call before it releases memory that is still used by
> the sv variable that PyErr_SetString() uses as argument, because sv
> points into memory owned by so.
>
> Patch is attached. This should be backpatched back to 8.0, where this
> code was introduced.
>
> I also threw in a couple of volatile declarations for variables that are
> used before and after the TRY. I don't think they caused the crash that
> I observed, but they could become issues.

This patch has been applied to 8.0 - 8.5.

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