linux-kernel - Re: [PATCH 1/2] y2038: make CONFIG_64BIT

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Message-ID: <CAK8P3a2UVqg--Xs29o55QbsRKu-ynN8ZXR96Phiq2cuCoABvGw@mail.gmail.com>
Date:   Mon, 29 Apr 2019 15:22:02 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Joseph Myers <joseph@...esourcery.com>,
        GNU C Library <libc-alpha@...rceware.org>,
        Linux API <linux-api@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Deepa Dinamani <deepa.kernel@...il.com>,
        Lukasz Majewski <lukma@...x.de>,
        Stepan Golosunov <stepan@...osunov.pp.ru>
Subject: Re: [PATCH 1/2] y2038: make CONFIG_64BIT_TIME unconditional

On Mon, Apr 29, 2019 at 9:34 AM Thomas Gleixner <tglx@...utronix.de> wrote:
>
> On Fri, 26 Apr 2019, Arnd Bergmann wrote:
>
> > As Stepan Golosunov points out, we made a small mistake in the
> > get_timespec64() function in the kernel. It was originally added under
> > the assumption that CONFIG_64BIT_TIME would get enabled on all 32-bit
> > and 64-bit architectures, but when I did the conversion, I only turned
> > it on for 32-bit ones.
> >
> > The effect is that the get_timespec64() function never clears the upper
> > half of the tv_nsec field for 32-bit tasks in compat mode. Clearing this
> > is required for POSIX compliant behavior of functions that pass a
> > 'timespec' structure with a 64-bit tv_sec and a 32-bit tv_nsec, plus
> > uninitialized padding.
> >
> > The easiest fix for linux-5.1 is to just make the Kconfig symbol
> > unconditional, as it was originally intended. As a follow-up,
> > we should remove any #ifdef CONFIG_64BIT_TIME completely.
> >
> > Link: https://lore.kernel.org/lkml/20190422090710.bmxdhhankurhafxq@sghpc.golosunov.pp.ru/
> > Cc: Lukasz Majewski <lukma@...x.de>
> > Cc: Stepan Golosunov <stepan@...osunov.pp.ru>
> > Signed-off-by: Arnd Bergmann <arnd@...db.de>
> > ---
> > Please apply this one as a bugfix for 5.1
>
> Can you provide a 'Fixes: ....' tag please?

Ok, resent both patches now. I also took the chance to add a clarification
for the point that Lukasz missed on the first submission.

       Arnd