Calling sys.excepthook(1,'1',1) crashes 3.0:

Python 3.0b3+ (py3k:65987, Aug 23 2008, 10:04:31)
[GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys; sys.excepthook(1,'1',1)
Segmentation fault

gdb points at "PyException_GetTraceback  at Objects/exceptions.c:265
265         Py_XINCREF(base_self->traceback);"

This was found by Fusil and Victor Stinner (haypo) sent me a patch (see
attachment).

Thanks bpeterson for triaging :)

PS: I also think that issue3643 should be targeted to 3.0, as the
underlying issue is the same, it would be an easy way to segfault
python3.0 and has a clean patch available.