Re: [PATCH] Linux Kernel Markers

Ingo Molnar
2006-09-19T16:45:36Z

* Martin Bligh <mbligh@google.com> wrote:

> Andrew Morton wrote:
> >On Tue, 19 Sep 2006 09:04:43 -0700
> >Martin Bligh <mbligh@google.com> wrote:
> >
> >
> >>It seems like all we'd need to do
> >>is "list all references to function, freeze kernel, update all
> >>references, continue"
> >
> >
> >"overwrite first 5 bytes of old function with `jmp new_function'".
>
> Yes, that's simple. but slower, as you have a double jump. Probably a
> damned sight faster than int3 though.

modern CPUs will probably even optimize that intermediate jump away in
their BTB-ish caches. But in any case this would solve the function
pointer problem too.

Ingo