Fatal Python error: ceval: tstate mix-up

[Laszlo Nagy]

After upgrading my system, a program started to throw this error, and 
make a core dump:

Fatal Python error: ceval: tstate mix-up

Kernel log says:

Jan  9 05:06:49 shopzeus kernel: pid 89184 (python), uid 1024: exited on 
signal 6 (core dumped)


I found out that this can happen only when executing Python code without 
holding the GIL. My program is written entriely in Python, but uses some 
third part libraries:

py25-json
py25-psycopg2

Here is Python version:

Python 2.5.2 (r252:60911, Nov 17 2008, 22:19:20)
[GCC 4.2.1 20070719  [FreeBSD]] on freebsd7

(OS is FreeBSD 7.0 amd64 stable on dual quad core xeon 5420, it that 
matters...)

I have the code dump, but I do not know how to debug that. What should I do?

Thanks,

   Laszlo