Linux kernel bug AMD64 - affects skiplists

[Bron Gondwana]

I promised I'd have something to say about skiplists soon!

(hi Rudy - hope you had a good time off, leaving me here to
figure this out _all_by_myself_ ;) )

There's a bug in the linux kernel for amd64 builds only
that breaks some skiplist files.

Specifically, checkpointing a seen file with a long (greater
than page size) list of seen data will cause corruption where
it crosses the page break.  The last 16-24 bytes will of the
page will be NULLed out.

You can read more about it in all its gory detail here:

http://lkml.org/lkml/2008/6/17/9

Thanks Linus for the prompt (at least partial) fix.

If you are running one of those kernels now, I recommend you
either change the kernel version, or apply the patch Linus
posted.  I was going to suggest a little "magic" patch, but
I've been unable to actually make it work in testing, so I
won't do it!

Bron.