Logged In: YES 
user_id=1404983

I've got a patch for the ParseTuple cases, but I don't seem
to be able to attach it. For now it is available from
http://www.tortall.net/mu/static/fmtcheck_parsetuple_41738_diff?raw

It consists mostly of replacing signed formats with unsigned
formats, and adding parse_foo temporary variables for
parsing to a known size. There's also a couple cases where I
just change the variable type to match the format when I'm
fairly certain it's safe. I added the test on this ticket to
test_mmap.py but added no other tests.