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    SubjectRe: CONFIG_MARKERS
    * Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) wrote:
    > * Frank Ch. Eigler (fche@redhat.com) wrote:
    > > Hi -
    > >
    > > On Tue, Jan 22, 2008 at 11:17:40PM -0500, Jon Masters wrote:
    > > > On Tue, 2008-01-22 at 22:10 -0500, Mathieu Desnoyers wrote:
    > > > > [...]
    > > > > > > Is this an attempt to not set a marker for proprietary modules? [...]
    > > > > >
    > > > > > I can't seem to find any discussion about this aspect. If this is the
    > > > > > intent, it seems misguided to me. There may instead be a relationship
    > > > > > to TAINT_FORCED_{RMMOD,MODULE}. Mathieu?
    > >
    > > > > On my part, its mostly a matter of not crashing the kernel when someone
    > > > > tries to force modprobe of a proprietary module (where the checksums
    > > > > doesn't match) on a kernel that supports the markers. Not doing so
    > > > > causes the markers to try to find the marker-specific information in
    > > > > struct module which doesn't exist and OOPSes.
    > >
    > > But you have the wrong target: it is not proprietary modules that have
    > > this risk but those built out-of-tree without checksums. Maybe
    > > oopsing in this case is not so bad; or the check could just limit itself to
    > > FORCED_MODULE.
    > >
    >
    > I guess that for this one I could have a :
    >
    > if (!mod->taints & TAINT_FORCED_MODULE)
    > ...
    >

    as one could notice: missing parenthesis
    if (!(mod->taints & TAINT_FORCED_MODULE))

    >
    > >
    > > > > Christoph's point of view is rather more drastic than mine : it's not
    > > > > interesting for the kernel community to help proprietary modules writers,
    > > > > so it's a good idea not to give them marker support. (I CC'ed him so he
    > > > > can clarify his position).
    > > > Right. I thought that was your collective opinion
    > >
    > > Another way of looking at this though is that by allowing/encouraging
    > > proprietary module writers to include markers, we and their users get
    > > new diagnostic capabilities. It constitutes a little bit of opening
    > > up, which IMO we should reward rather than punish.
    > >
    > >
    >
    > This specific one is a kernel policy matter, and I personally don't
    > have a strong opinion about it. I agree that you raise a good counter
    > argument : it can be useful to proprietary modules users to be able to
    > extract tracing information from those modules to argue with their
    > vendors that their driver/hardware is broken (a tracer is _very_ useful
    > in that kind of situation). However, it is also useful to proprieraty
    > module writers who can benefit from the merged kernel/modules traces.
    > Do we want to give them this ability ? It would surely help writing
    > better proprieraty kernel modules. Do we want this, or rather prefer to
    > put more pressure on them so they open their code ?
    >
    > I will let others fight in the mud on this one. :)
    >
    > for this one, we could add, instead :
    >
    > if (!mod->taints & (TAINT_FORCED_MODULE | TAINT_PROPRIETARY_MODULE))
    >

    here too
    if (!(mod->taints & (TAINT_FORCED_MODULE | TAINT_PROPRIETARY_MODULE)))

    Which remembers me to never write code before my first coffee in the
    morning ;)

    Mathieu

    > Mathieu
    >
    > > - FChE
    >
    > --
    > Mathieu Desnoyers
    > Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
    > OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68

    --
    Mathieu Desnoyers
    Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
    OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68


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