Kernel Linux Debugging

Does anybody have experience of Linux Debugging? What methods and utilities did you use?
Would you please share your experience?

Thanks in advance

for kernel debugging...there are various tools...patches available..
1 : kgdb is one..which requires the kernel to be compiled with -g option and having the kgdb patch applied to the kernel..but kgdb requires a null modem and two machines..
2:there is kdb that doesnt require any extra machine ..but patches the kernel..requires a bit of understanding of assembly ..
3: there are toolkits like linux trace toolkit,
4: 2.6 series has kprobes..that can be used to insert prints in a running kernel..
5: also, you can see the kernel hacking subsection of the kernel configuration to configure the kernel to have certain features turned on to enable debugging or traces...like SLAB_DEBUG to perform slab allocation debugging..
these are some of the things ...

Hi guys
I know about these utilities.
I need a good GUIDES and HOWTOS how to use them.
Step by step instructions like, for example, compiling kernel
Has anybody experience of debugging kernel using these utilities?
Any body can give me these instructions
Using the following utilities and techniques
The main ones:
GDB
KDB
KPROBES

and also
KGDB
UML
LTT


Any experience sharing, links, info etc are appreciated
Thank you in advance