[CentOS] How do I debug the kernel?

Tue Mar 6 22:40:30 UTC 2007
James Olin Oden <james.oden at gmail.com>

On 3/6/07, Rodrigo Barbosa <rodrigob at darkover.org> wrote:
> Hash: SHA1
> On Tue, Mar 06, 2007 at 04:38:21PM -0500, James Olin Oden wrote:
> > On 3/6/07, Rodrigo Barbosa <rodrigob at darkover.org> wrote:
> > >> >Humm, not that I know of. And considering we are talking about PC
> > >hardware
> > >> >here (are we?), I can't imagine how it can be possible.
> > >> I'm definately no expert here, but PC hardware has many hardware level
> > >> debuging hooks that apps such as oprofile take advantage of.
> > >
> > >Sure does, but how does one recover from a hardware lockup ?
> > >
> > Well say the PCI buses timing gets hosed and the whole system seizes
> > up what do you intened to do at that point (that is a hardware
> > lockup)?  And what does that thing you do have to do with debuging a
> > kernel?  Just curious.
> A hardware lockup can be induced by software (quite easily, actually).
I'm still not following you.  Its one thing for the "kernel" to lockup
and its another for the hardware to lockup.  Could you give an

> On a 2 computers debug environment, you can see it happening and get
> enough data to fix it.
Provided the processor is still functioning in some way, sure.

> > >Even if it were possible to have that kind of debugging, it would be
> > >fairly limited.
> > When you say "hardware" I start thinking jtag interfaces, or even more
> > interesting was this thing we would place every pin of the processor
> > through and then connect to the socket on the motherboard, but I think
> > I missing something.
> Oh, I remember that one. SoftICE it was called, I think. I'm not sure.
> That was many years ago. Yes, that is one option but, if I remember correctly,
> that debugging hardware had a small processor of its own, completely
> independant.
> And yes, jtag is also quite nice, but I never saw anything like that on a
> PC. Used them on some MIPS boards.
Its definately on higher end Intel and AMD boards.