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    SubjectRe: [RFC][PATCH 0/4] Fixes for two recently found timekeeping bugs

    * John Stultz <john.stultz@linaro.org> wrote:

    > As part of the Linaro Linux Kernel Functional Test (LKFT)
    > effort, test failures from kselftest/timer's
    > inconsistency-check were reported connected to
    > CLOCK_MONOTONIC_RAW, on the HiKey platform.
    >
    > Digging in I found that an old issue with how sub-ns accounting
    > is handled with the RAW time which was fixed long ago with the
    > CLOCK_MONOTONIC/REALTIME ids, but missed with RAW time, was
    > present.
    >
    > Additionally, running further tests, I uncovered an issue with
    > how the clocksource read function is handled when clocksources
    > are changed, which can cause crashes.
    >
    > Both of these issues have not been uncovered in x86 based
    > testing due to x86 not using vDSO to accelerate
    > CLOCK_MONOTONIC_RAW, combined with the HiKey's arch_timer
    > clocksource being fast to access but incrementing slowly enough
    > to get multiple reads using the same counter value (which helps
    > uncover time handing issues), along with the fact that none of
    > the x86 clocksources making use of the clocksource argument
    > passed to the read function.
    >
    > This patchset addresses these two issues.

    AFAICS only the first two patches are fixes, the other two patches are
    cleanups/simplifications that resulted out of the debugging effort, right?

    Thanks,

    Ingo

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