I was saying that for practical purposes, debugging the kernel is needlessly hard.
As one example, say you are running the current ubuntu. A kernel panic will give you a bunch of hex addresses. How do you get a symbol'd backtrace of the kernel panic?
(if you can't get that easily, running kgdb won't let you do symbolic debugging either)
For really hairy bugs in programs that can't be stopped (kernel/drivers/realtime, etc) logging works.
And when it doesn't, like when you can't do I/O or switching of any kind, log non-blocking to a buffer that is dumped elsewhere.
also, related. It is harder than it should be to debug the linux kernel. Just getting a symboled stack trace is ridiculously hard.