Re: [PATCH] kprobes/x86: Return correct length in __copy_instruction()

From: Masami Hiramatsu
Date: Tue Mar 17 2015 - 05:45:44 EST


(2015/03/17 0:03), Ingo Molnar wrote:
>
> * Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
>
>> (2015/03/09 20:19), Eugene Shatokhin wrote:
>>> On x86-64, __copy_instruction() always returns 0 (error) if the
>>> instruction uses %rip-relative addressing. This is because
>>> kernel_insn_init() is called the second time for 'insn' instance
>>> in such cases and sets all its fields to 0.
>>>
>>> Because of this, trying to place a Kprobe on such instruction will
>>> fail, register_kprobe() will return -EINVAL.
>>
>> Oops, good catch!
>>
>> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
>
> Mind resending it with your SOB, as I wasn't Cc:-ed on the original
> submission?

Yes, I'll do :)

Thank you,

>
> Thanks,
>
> Ingo
>


--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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