Messages in this thread |  | | Date | Fri, 06 Dec 2013 11:34:30 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs |
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(2013/12/05 19:21), Ingo Molnar wrote: > > * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote: > >>> So we need both a maintainable and a sane/safe solution, and I'd >>> like to apply the whole thing at once and be at ease that the >>> solution is round. We should have done this years ago. >> >> For the safeness of kprobes, I have an idea; introduce a whitelist >> for dynamic events. AFAICS, the biggest unstable issue of kprobes >> comes from putting *many* probes on the functions called from >> tracers. > > If the number of 'noprobe' annotations is expected to explode then > maybe another approach should be considered.
No, since this is a "quantitative" issue, the annotation helps us.
> For example in perf we detect recursion. Could kprobes do that and > detect hitting a probe while running kprobes code, and ignore it [do > an early return]?
Yes, the kprobe itself already has recursion detector and it rejects calling handler.
> > That way most of the annotations could be removed and kprobes would > become inherently safe. Is there any complication I'm missing?
That is actually what I'm doing with cleanup patches. :)
Thank you,
-- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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