Re: [PATCH -tip v5 03/10] kprobes: Introduce kprobes jump optimization

Steven Rostedt
2009-11-25T21:08:48Z

On Tue, 2009-11-24 at 15:59 -0500, Masami Hiramatsu wrote:

> > I see...so the non-preemptible kernel requirement looks
> > hard to workaround :-s
>
> It's the next challenge I think :-)
> Even though, kprobes itself still work on preemptive kernel,
> so we don't lose any functionality.

>From kstop_machine, we could search all tasks to see if any are about to
resume in the modified location. If there is, we could either

1) insert a normal kprobe
2) modify the return address of the task to jump to some trampoline to
finish the work and return to the code spot with a direct jump.

#2 is kind of nasty but seems like a fun thing to implement ;-)

-- Steve