Re: Re: [PATCH 1/5] ftrace: Synchronize variable setting withbreakpoints

[Masami Hiramatsu]

(2012/05/31 23:08), Steven Rostedt wrote:
> Now Masami said he thinks the text_poke should also do the change of
> kernel protection as well, and not do the FIXMAP mapping. At least for
> bulk changes. The added breakpoint code that we have can be shared
> between ftrace and text_poke. That is something we want to do. After we
> get ftrace working, we'll go ahead and make it work for text_poke as
> well ;-)

Indeed, ftrace can be a better test case for breakpoint-based self-
modifying. So after we can make sure that is safely work on x86
widely, it is better to rewrite text_poke with that method.

Perhaps, kprobes-*jump*-optimization may be better to handle it
because the target probe is simultaneously working while
optimizing (modifying code). This means that if someone hits
breakpoint of such kprobe, it must be handled by kprobes, not
only just tweaking IP address.

Thank you,

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/