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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Sat, 24 Nov 2018 09:24:41 +0100
Message-ID: <CANiq72miapoMHiXsq-gSu5+dhpGDE6Dnf3c_6DpHRkwNiPPU6g@mail.gmail.com>
Subject: Re: [PATCH v4 1/3] kernel.h: disable type-checks in container_of()
 for Sparse
To:     Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc:     Masahiro Yamada <yamada.masahiro@socionext.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Kees Cook <keescook@chromium.org>, josh@joshtriplett.org,
        ast@kernel.org, linux-kernel <linux-kernel@vger.kernel.org>,
        neilb@suse.com, Greg KH <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>, cmo@melexis.com,
        Dan <dan.carpenter@oracle.com>
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On Fri, Nov 23, 2018 at 10:14 PM Luc Van Oostenryck
<luc.vanoostenryck@gmail.com> wrote:
>
> On Thu, Nov 22, 2018 at 12:14:20PM +0900, Masahiro Yamada wrote:
> > When I tried to enable BUILD_BUG_ON for Sparse, the kbuild test robot
> > reported lots of "unknown expression" warnings from container_of(),
> > which seemed false positive.
> >
> > I addressed this in [1], but fixing Sparse is the right thing to do.
> >
> > The issue was fixed by Sparse commit 0eb8175d3e9c ("fix expansion of
> > function designator"), but it will take time until the fixed version
> > of Sparse is widely available.
> >
> > Disable the container_of() type checks for Sparse for now.
>
> I would prefer that developers upgrade their version of sparse but ...
>
> Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>

Indeed. If someone is writing code for the latest kernels, I think it
is reasonable to assume they are able to use the latest sparse too,
since it is not required for compilation anyway.

Cheers,
Miguel