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    SubjectRe: [RFC] [PATCH] cpuset operations causes Badness at mm/slab.c:777 warning
    On Fri, 1 Jun 2007 13:47:23 -0700 (PDT)
    Christoph Lameter <clameter@sgi.com> wrote:

    > On Fri, 1 Jun 2007, Jeremy Fitzhardinge wrote:
    >
    > > I think this is a good example of why having to special-case kmalloc(0)
    > > is a bad idea. The original code was straightforward and, barring
    > > silliness, should be completely correct with npids==0. This new code
    > > does nothing other than make things more complex.
    >
    > Hehe we got you. The code is indexing the pidarray allocated with
    > kmalloc(0). So it uncovered a latent bug. It only worked because SLAB gave
    > him 32 bytes and it now only works because SLUB give him 8. That is enough
    > to illegally index the first array element.
    >

    Poisoning and redzoning could have caught that.

    But I guess it doesn't matter now, as this shortcoming is specific to
    the zero-length allocations, and we're weeding those out anyway.
    -
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