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From:   Vincent Guittot <vincent.guittot@linaro.org>
Date:   Mon, 21 Jun 2021 19:44:13 +0200
Message-ID: <CAKfTPtCwqpHUxFdk0Q4dwL19Zn0_EhX7gQ8dwf=rsWHyxZVAVw@mail.gmail.com>
Subject: Re: [powerpc][5.13.0-rc7] Kernel warning (kernel/sched/fair.c:401)
 while running LTP tests
To:     Sachin Sant <sachinp@linux.vnet.ibm.com>
Cc:     Peter Zijlstra <peterz@infradead.org>, Odin Ugedal <odin@uged.al>,
        linuxppc-dev@lists.ozlabs.org,
        open list <linux-kernel@vger.kernel.org>
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On Mon, 21 Jun 2021 at 19:32, Sachin Sant <sachinp@linux.vnet.ibm.com> wrote:
>
> >>> Any thoughts Vincent?
> >>
> >>
> >> I would prefer that we use the reason of adding the cfs in the list instead.
> >>
> >> Something like the below should also fixed the problem. It is based on a
> >> proposal I made to Rik sometimes ago when he tried to flatten the rq:
> >> https://lore.kernel.org/lkml/20190906191237.27006-6-riel@surriel.com/
> >>
> >> This will ensure that a cfs is added in the list whenever one of its  child
> >> is still in the list.
> >
> > Could you confirm that this patch fixes the problem for you too ?
> >
> Thanks for the fix.
>
> The patch fixes the reported problem. The test ran to completion without
> any failure.
>
> Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>

Thanks

>
> -Sachin
>