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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 15 Sep 2020 14:45:20 +0200
Message-ID: <CAK8P3a2WG0DvTyrTkiLg3GW1x2s-oo8BgAyvp7uHvzXhJCiHmQ@mail.gmail.com>
Subject: Re: [PATCH] time: Avoid undefined behaviour in timespec64_to_ns
To:     "Zengtao (B)" <prime.zeng@hisilicon.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Tue, Sep 15, 2020 at 2:20 PM Zengtao (B) <prime.zeng@hisilicon.com> wrote:

> > > Fixes: bd40a175769d ("y2038: itimer: change implementation to
> > timespec64")
> >
> > This one caused the regression, but if we add the check here, it
> > may be best to also add it in prior kernels that may have the same
> > bug in other callers of the same function. Maybe backport all the
> > way to stable kernels that first added timespec64?
> >
>
> I think we need to do the backport, but not sure about the start point
> Thanks for your review.

I would suggest

Cc: <stable@vger.kernel.org> # v3.17+
Fixes: 361a3bf00582 ("time64: Add time64.h header and define struct timespec64")

       Arnd