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    SubjectRe: [PATCH] MTRR: Fix race causing set_mtrr to go into infinite loop
    Date
    On Tuesday 26 June 2007 00:05:17 Chuck Ebbert wrote:
    > On 06/25/2007 05:38 PM, Loic Prylli wrote:
    >
    > [cc: Andi]
    >
    > > Processors synchronization in set_mtrr requires the .gate field
    > > to be set after .count field is properly initialized. Without an explicit
    > > barrier, the compiler was reordering those memory stores. That was sometimes
    > > causing a processor (in ipi_handler) to see the .gate change and
    > > decrement .count before the latter is set by set_mtrr() (which
    > > then hangs in a infinite loop with irqs disabled).

    Hmm, perhaps we should just put the smp_wmb into atomic_set().
    Near all other atomic operations have memory barriers too. I think
    that would be the better fix.

    -Andi
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