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From:   Marco Elver <elver@google.com>
Date:   Tue, 19 Nov 2019 17:12:16 +0100
Message-ID: <CANpmjNMpnY54kDdGwOPOD84UDf=Fzqtu62ifTds2vZn4t4YigQ@mail.gmail.com>
Subject: Re: linux-next: Tree for Nov 19 (kcsan)
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Stephen Rothwell <sfr@canb.auug.org.au>,
        Linux Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "Paul E. McKenney" <paulmck@kernel.org>
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On Tue, 19 Nov 2019 at 16:11, Randy Dunlap <rdunlap@infradead.org> wrote:
>
> On 11/19/19 12:46 AM, Stephen Rothwell wrote:
> > Hi all,
> >
> > Changes since 20191118:
> >
>
> on x86_64:
>
> It seems that this function can already be known by the compiler as a
> builtin:
>
> ../kernel/kcsan/core.c:619:6: warning: conflicting types for built-in fun=
ction =E2=80=98__tsan_func_exit=E2=80=99 [-Wbuiltin-declaration-mismatch]
>  void __tsan_func_exit(void)
>       ^~~~~~~~~~~~~~~~
>
>
> $ gcc --version
> gcc (SUSE Linux) 7.4.1 20190905 [gcc-7-branch revision 275407]

Interesting. Could you share the .config? So far I haven't been able
to reproduce.

I can get the warning if I manually add -fsanitize=3Dthread to flags for
kcsan/core.c (but normally disabled via KCSAN_SANITIZE :=3D n). If
possible could you also share the output of `make V=3D1` for
kcsan/core.c?

Thanks,
-- Marco

> --
> ~Randy
> Reported-by: Randy Dunlap <rdunlap@infradead.org>