Just updated the Raspberry Pi from (hacked!)3.8.0 to 3.8.1, by applying the 3.8.0-1 patch at ftp://ftp.kernel.org/pub/linux/kernel/v3.0/patch-3.8.1.bz2
Note that this first incremental patch is in the ‘main’ kernel directory.   Only the subsequent ones (3.8.1-2, etc..) will be in the /incr subdirectory..

The patch applied cleanly, and all seems to be working OK:

Fedora release 18 (Spherical Cow)
Kernel 3.8.1-pi on an armv6l (ttyAMA0)
………………………
$ uname -a
Linux rgpi 3.8.1-pi #1 Thu Feb 28 19:02:44 GMT 2013 armv6l armv6l armv6l GNU/Linux

Robert Gadsdon.  February 28th, 2013.