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    SubjectRe: [PATCH -tip v5 07/10] kprobes/x86: Support kprobes jump optimization on x86
    Masami Hiramatsu wrote:
    > Jason Baron wrote:
    >> Also, with multiple users we don't want to trample over each others code
    >> patching. Thus, if each sub-system could register some type of
    >> 'is_reserved()' callback, and then we can call all these call backs from
    >> the '__multibyte_poke()' routine before we do any patching to make sure
    >> that we aren't trampling on each others code. After a successful
    >> patching, each sub-system can update its reserved set of code as
    >> appropriate. I can code a prototype here, if this makes sense.
    > Hmm, we have to implement it carefully, because here kprobes already
    > inserted int3 and optprobe rewrites the int3 again. If is_reserved()
    > returns 1 and multibyte_poke returns error, we can't optimize it anymore.

    IMHO, all text-modifiers except kprobes provide is_reserved() callback
    and kprobes cancels probing if its target address is reserved, since
    only kprobes changes texts anywhere while others changes texts at
    fixed addresses.

    Anyway, I think this will be another bugfix for current kprobes/alternative.

    Thank you,
    Masami Hiramatsu

    Software Engineer
    Hitachi Computer Products (America), Inc.
    Software Solutions Division


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