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    SubjectRe: [RFC PATCH 1/1] mm/percpu.c: fix memory leakage issue when allocate a odd alignment area
    On Wed 12-10-16 08:28:17, zijun_hu wrote:
    > On 2016/10/12 1:22, Michal Hocko wrote:
    > > On Tue 11-10-16 21:24:50, zijun_hu wrote:
    > >> From: zijun_hu <zijun_hu@htc.com>
    > >>
    > >> the LSB of a chunk->map element is used for free/in-use flag of a area
    > >> and the other bits for offset, the sufficient and necessary condition of
    > >> this usage is that both size and alignment of a area must be even numbers
    > >> however, pcpu_alloc() doesn't force its @align parameter a even number
    > >> explicitly, so a odd @align maybe causes a series of errors, see below
    > >> example for concrete descriptions.
    > >
    > > Is or was there any user who would use a different than even (or power of 2)
    > > alighment? If not is this really worth handling?
    > >
    >
    > it seems only a power of 2 alignment except 1 can make sure it work very well,
    > that is a strict limit, maybe this more strict limit should be checked

    I fail to see how any other alignment would actually make any sense
    what so ever. Look, I am not a maintainer of this code but adding a new
    code to catch something that doesn't make any sense sounds dubious at
    best to me.

    I could understand this patch if you see a problem and want to prevent
    it from repeating bug doing these kind of changes just in case sounds
    like a bad idea.
    --
    Michal Hocko
    SUSE Labs

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