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From:   Olof Johansson <olof@lixom.net>
Date:   Fri, 2 Nov 2018 14:27:42 -0700
Message-ID: <CAOesGMi-vkYPDrL2drJ70zf3_xTMWrsfPoW68TkiRJCj8uWBLg@mail.gmail.com>
Subject: Re: [PATCH] ubsan: don't mark __ubsan_handle_builtin_unreachable as noreturn
To:     aryabinin@virtuozzo.com
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Nicolas Pitre <nico@linaro.org>,
        Andi Kleen <ak@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Feb 5, 2018 at 2:31 AM Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
>
> On 02/05/2018 01:15 PM, Arnd Bergmann wrote:
> > On Mon, Feb 5, 2018 at 10:02 AM, Andrey Ryabinin
> > <aryabinin@virtuozzo.com> wrote:
> >>
> >>
> >> On 02/02/2018 06:47 PM, Arnd Bergmann wrote:
> >>> gcc-8 complains about the prototype for this function:
> >>>
> >>> lib/ubsan.c:432:1: error: ignoring attribute 'noreturn' in declaration of a built-in function '__ubsan_handle_builtin_unreachable' because it conflicts with attribute 'const' [-Werror=attributes]
> >>>
> >>
> >> That's actually a bug in GCC. In GCC __ubsan_handle_builtin_unreachable declared
> >> with 'noreturn' and 'const' attributes:
> >>
> >> DEF_SANITIZER_BUILTIN(BUILT_IN_UBSAN_HANDLE_BUILTIN_UNREACHABLE,
> >>                       "__ubsan_handle_builtin_unreachable",
> >>                       BT_FN_VOID_PTR,
> >>                       ATTR_COLD_CONST_NORETURN_NOTHROW_LEAF_LIST)
> >>
> >>
> >> But const attribute doesn't make any sense for function that returns void or doesn't return at all.
> >> Given that gcc-8 has not released yet, it would be better to fix this bug there.
> >
> > Ok. Should I open a gcc bug, or will you take care of it?
> >
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84210

8.2.0 still shows this, and there's been no movement on that bug. How
about we pick up this patch until it's been resolved?


-Olof