Thank you for sharing, this is a very good reading.
I purchased a book about using buffer overflow to hack stuff. but I'm wondering how those kernel bugs were discovered?
It's probably one of the best technical security related books I've ever read.
Hacking: The Art of Exploitation, 2nd Edition
A Guide to Kernel Exploitation: Attacking the Core
...if you're interested in the kernel level exploits.
disclaimer: A co-worker of mine co-authored it.