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    SubjectRe: next/master bisection: baseline.login on rk3288-rock2-square
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    On 04/02/2021 10:27, Ard Biesheuvel wrote:
    > On Thu, 4 Feb 2021 at 11:06, Russell King - ARM Linux admin
    > <linux@armlinux.org.uk> wrote:
    >>
    >> On Thu, Feb 04, 2021 at 10:07:58AM +0100, Ard Biesheuvel wrote:
    >>> On Thu, 4 Feb 2021 at 09:43, Guillaume Tucker
    >>> <guillaume.tucker@collabora.com> wrote:
    >>>>
    >>>> Hi Ard,
    >>>>
    >>>> Please see the bisection report below about a boot failure on
    >>>> rk3288 with next-20210203. It was also bisected on
    >>>> imx6q-var-dt6customboard with next-20210202.
    >>>>
    >>>> Reports aren't automatically sent to the public while we're
    >>>> trialing new bisection features on kernelci.org but this one
    >>>> looks valid.
    >>>>
    >>>> The kernel is most likely crashing very early on, so there's
    >>>> nothing in the logs. Please let us know if you need some help
    >>>> with debugging or trying a fix on these platforms.
    >>>>
    >>>
    >>> Thanks for the report.
    >>
    >> Ard,
    >>
    >> I want to send my fixes branch today which includes your regression
    >> fix that caused this regression.
    >>
    >> As this is proving difficult to fix, I can only drop your fix from
    >> my fixes branch - and given that this seems to be problematical, I'm
    >> tempted to revert the original change at this point which should fix
    >> both of these regressions - and then we have another go at getting rid
    >> of the set/way instructions during the next cycle.
    >>
    >> Thoughts?
    >>
    >
    > Hi Russell,
    >
    > If Guillaume is willing to do the experiment, and it fixes the issue,

    Yes, I'm running some tests with that fix now and should have
    some results shortly.

    > it proves that rk3288 is relying on the flush before the MMU is
    > disabled, and so in that case, the fix is trivial, and we can just
    > apply it.
    >
    > If the experiment fails (which would mean rk3288 does not tolerate the
    > cache maintenance being performed after cache off), it is going to be
    > hairy, and so it will definitely take more time.
    >
    > So in the latter case (or if Guillaume does not get back to us), I
    > think reverting my queued fix is the only sane option. But in that
    > case, may I suggest that we queue the revert of the original by-VA
    > change for v5.12 so it gets lots of coverage in -next, and allows us
    > an opportunity to come up with a proper fix in the same timeframe, and
    > backport the revert and the subsequent fix as a pair? Otherwise, we'll
    > end up in the situation where v5.10.x until today has by-va, v5.10.x-y
    > has set/way, and v5.10y+ has by-va again. (I don't think we care about
    > anything before that, given that v5.4 predates any of this)
    >
    > But in the end, I'm happy to go along with whatever works best for you.

    Thanks,
    Guillaume

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