Messages in this thread | | | Date | Fri, 13 Dec 2013 15:06:06 +0900 | From | Masami Hiramatsu <> | Subject | Re: Re: Re: [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs |
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(2013/12/13 14:34), Masami Hiramatsu wrote: >> Lets assume we allow a probe to be inserted in the single-step path. >> Such a probe will be an INT3 instruction and if it hits we get a >> recursive INT3 invocation. In that case the INT3 handler should simply >> restore the original instruction and _leave it so_. There's no >> single-stepping needed - the probe is confused and must be discarded. > > But how can we restore the protected kernel text? > If we use text_poke, we also need to prohibit probing on the text_poke > and functions called in the text_poke too. That just shifts the annotated > area to the text_poke. :(
BTW, currently we mark the text_poke as nokprobe_symbol, but it should be removed. We don't call it from kprobes int3/debug handlers.
The patches which removes __kprobes in this series are only for kprobe related files (arch/x86/kernel/kprobes/* or kernel/kprobes.c.) I think we should do it for other parts. Is it better to do that on this series?
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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