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    SubjectRe: [rfc][patches] fix for munmap/truncate races
    On Sun, Mar 18, 2012 at 10:06:10PM +0000, Al Viro wrote:
    > On Sun, Mar 18, 2012 at 03:01:08PM -0700, Linus Torvalds wrote:
    > > On Sun, Mar 18, 2012 at 12:07 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
    > > > - ? ? ? tlb_finish_mmu(&tlb, 0, end);
    > > > + ? ? ? tlb_finish_mmu(&tlb, 0, -1);
    > >
    > > Hmm. The fact that you drop the end pointer means that some
    > > architectures that optimize the TLB flushing for ranges now
    > > effectively can't do it any more.
    > >
    > > Now, I think it's only ia64 that really is affected, but it *might* matter.
    > >
    > > In particular, ia64 has some logic for "if you only flush one single
    > > region, you can optimize it", and the region sizes are in the
    > > terabytes. And I'm pretty sure you broke that - I'm just not entirely
    > > sure how much we care.
    >
    > Nope - ia64 check explicitly for precisely that case:
    [snip]
    ... and everything else doesn't look at start or end at all.


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