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    SubjectRe: [BK PATCH 1/4] remove NGROUPS hard limit (resend)
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    > +void
    > +qsort(void *a, size_t n, size_t es, cmp_t *cmp)
    > +{
    > + char *pa, *pb, *pc, *pd, *pl, *pm, *pn;

    A recursive algorithm fed user controlled input that dictates how much
    it recurses, in a kernel with a stack limit. Oh and since qsort is
    O(N^2) worst case and the user controls the input thats another concern.

    > + if ((r = pb - pa) > es)
    > + qsort(a, r / es, es, cmp);
    > + if ((r = pd - pc) > es) {
    > + /* Iterate rather than recurse to save stack space */


    I find it hard to believe that a simple bucket sort wouldnt perform as
    well in real life and with a defined time/space, or even something like
    shell metzner if you want trivial with good typical behaviour.

    Alternatively you could just do a merge pass when a new set of groups is
    added.

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