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    From
    SubjectRe: [PATCH] 2.4.0 i386 watchpoint problems
    Date
    Followup to:  <Pine.LNX.4.10.10009211031370.1348-100000@penguin.transmeta.com>
    By author: Linus Torvalds <torvalds@transmeta.com>
    In newsgroup: linux.dev.kernel
    >
    > Actually, even simpler approach:
    >
    > - always clear db7 after sending signal - don't test for pending or for
    > kernel mode at all at that point.
    > - re-load %db7 at the top of the for(;;) loop in do_signal().
    >
    > That should mean that you will actually get a debug signal for ALL
    > triggers of the debug registers, except you'll only get one for kernel
    > mode.
    >
    > (For extra credit, make the patch use "eip=-1" in the siginfo structure if
    > the trap happened in kernel mode, so that we don't leak kernel addresses
    > to user space. Not that it would be much of a security issue, but it's a
    > beauty wart that could easily be cleared up).
    >

    It could be (and so would even giving the signals in kernel
    mode)... remember that silly case of passwords crossing page
    boundaries?

    -hpa
    --
    <hpa@transmeta.com> at work, <hpa@zytor.com> in private!
    "Unix gives you enough rope to shoot yourself in the foot."
    http://www.zytor.com/~hpa/puzzle.txt
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