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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 28 May 2020 00:29:51 +0200
Message-ID: <CAK8P3a1YHS0kQODqKEqZ5DJCSodyOWE=G5i0pjoPq_V0pQDauA@mail.gmail.com>
Subject: Re: [PATCH] binfmt_elf_fdpic: fix execfd build regression
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Kees Cook <keescook@chromium.org>,
        =?UTF-8?Q?Valdis_Kl=C4=93tnieks?= <valdis.kletnieks@vt.edu>,
        Greg Ungerer <gerg@linux-m68k.org>,
        Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Thu, May 28, 2020 at 12:12 AM Eric W. Biederman
<ebiederm@xmission.com> wrote:
>
> Arnd Bergmann <arnd@arndb.de> writes:
>
> > The change to bprm->have_execfd was incomplete, leading
> > to a build failure:
> >
> > fs/binfmt_elf_fdpic.c: In function 'create_elf_fdpic_tables':
> > fs/binfmt_elf_fdpic.c:591:27: error: 'BINPRM_FLAGS_EXECFD' undeclared
> >
> > Change the last user of BINPRM_FLAGS_EXECFD in a corresponding
> > way.
> >
> > Reported-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
> > Fixes: b8a61c9e7b4a ("exec: Generic execfd support")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > I have no idea whether this is right, I only looked briefly at
> > the commit that introduced the problem.
>
> It is correct and my fault.
>
> Is there an easy to build-test configuration that includes
> binfmt_elf_fdpic?
>
> I have this sense that it might be smart to unify binfmt_elf
> and binftm_elf_fdpic to the extent possible, and that will take build
> tests.

It should be included in an ARM allmodconfig. Nicolas Pitr did the
work to support ELF_FDPIC on ARM with MMU a while ago, but
I'm not sure what it would take to make this architecture independent
or support build-testing on x86.

       Arnd