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    SubjectRe: Memory corruption due to word sharing
    On Wed, Feb 1, 2012 at 10:45 AM, Jeff Law <> wrote:
    > Torvald Riegel & I were told that was kernel policy when we brought up the
    > upcoming bitfield semantic changes with some of the linux kernel folks last
    > year.

    Btw, one reason this is true is that the bitfield ordering/packing is
    so unspecified that using bitfields sometimes is just way more pain
    than you get. Some people have tried to use bitfields for various IO
    data structures (think laying out bits in memory to match some
    particular layout of some disk controller result structure). It's
    always a total disaster, because you have another whole level of
    architecture-specific bit ordering (in *addition* to all the normal
    byte order issues).

    That's not a compiler issue, that's just the nature of the beast.
    It's just another reason why the kernel often ends up then doing bit
    masking by hand.

    But *all* that said, we do have a metric buttload of bitfields in the
    kernel. It's not some really unusual feature. It does get used a lot,
    despite all the reasons why some particular code might not use

    We have a lot of code, there's still a lot of situations left where
    bitfields are just really convenient.


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