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    SubjectRe: [RFC PATCH tip 0/5] tracing filters with BPF
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    Andi Kleen <andi@firstfloor.org> writes:

    > [...] While it sounds interesting, I would strongly advise to make
    > this capability only available to root. Traditionally lots of
    > complex byte code languages which were designed to be "safe" and
    > verifiable weren't really. e.g. i managed to crash things with
    > "safe" systemtap multiple times. [...]

    Note that systemtap has never been a byte code language, that avenue
    being considered lkml-futile at the time, but instead pure C. Its
    safety comes from a mix of compiled-in checks (which you can inspect
    via "stap -p3") and script-to-C translation checks (which are
    self-explanatory). Its risks come from bugs in the checks (quite
    rare), problems in the runtime library (rare), and problems in
    underlying kernel facilities (rare or frequent - consider kprobes).


    > So the likelyhood of this having some hole somewhere (either in
    > the byte code or in some library function) is high.

    Very true!


    - FChE


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