lkml.org 
[lkml]   [2013]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Re: Re: [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs
(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




\
 
 \ /
  Last update: 2013-12-13 07:41    [W:0.248 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site