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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Sun, 25 Nov 2018 22:56:23 +0900
Message-ID: <CAK7LNATVWmt9Eiy8s2wBbCGrWaus=j2b4NZ-OnEoTeph9x3dJw@mail.gmail.com>
Subject: Re: [PATCH v4 1/3] kernel.h: disable type-checks in container_of()
 for Sparse
To:     Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc:     Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Kees Cook <keescook@chromium.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        NeilBrown <neilb@suse.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>, cmo@melexis.com,
        Dan Carpenter <dan.carpenter@oracle.com>
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On Sat, Nov 24, 2018 at 6:06 PM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> 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.


I am OK with either way.

I leave this to Andrew.


-- 
Best Regards
Masahiro Yamada