git pack-objects run amok

[Christopher Faylor]

The load average on gcc.gnu.org was in the 300-400 range for a while
tonight.  The culprit was apparently due to a lot of these:

git pack-objects --revs --thin --stdout --delta-base-offset

I renamed /usr/local/bin/git to /usr/local/bin/git-saf and killed a
bunch of these to get the load average down so that I could do
something.  Then, eventually, I just killed the rest with 'SIGHUP'.

Looking at the logs, it looks like we had at least two git abusers:

    760 130.161.158.181
    303 195.113.20.142

So I blocked them via iptables.  When i renamed git back we started
to get flooded again from 169.237.4.230 so I blocked them too.

I have no idea what the fallout from this is going to be but I'll
leave that to the morning shift.  I have to be at the airport at
7AM and it's 1AM here so I can't do much more tonight.

cgf