Re: Dead Config in mm/percpu.c

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From: Christian Dietrich
Date: Wednesday, July 21, 2010 - 2:22 am

Hi all!
       
        As part of the VAMOS[0] research project at the University of
Erlangen we are looking at multiple integrity errors in linux'
configuration system.

        I've been running a check on the mm/ sourcetree for
config Items not defined in Kconfig and found 1 such case. Sourcecode
blocks depending on these Items are not reachable from a vanilla
kernel -- dead code. I've seen such dead blocks made on purpose
e.g. while integrating new features into the kernel but generally
they're just useless.

We found, that CONFIG_NEED_PER_CPU_KM is a dead symbol, so it isn't defined
anywhere. Cause of that the percpu_km.c is never included anywhere. Is
this a intended dead symbol, for use in out of tree development, or is
this just an error?

Regards
        Christian Dietrich
-- 
(λ x . x x) (λ x . x x) -- See how beatiful the lambda is
No documentation is better than bad documentation
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--

From: Tejun Heo
Date: Wednesday, July 21, 2010 - 8:12 am

Oh, it's new code waiting to be used.  It's for cases where SMP is
used w/o MMU.  IIRC, it was blackfin.

Thanks.

-- 
tejun
--

From: Mike Frysinger
Date: Monday, August 9, 2010 - 11:26 pm

yep.  unfortunately, we're in the middle of making a release on top of
2.6.34.x.  hopefully we should be able to get a patch out for the
2.6.37 merge window at the latest.
-mike
--

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