linux-kernel - Re: [PATCH 4/8] binfmt_elf: open code copy_siginfo_to

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Date:   Wed, 15 Apr 2020 10:20:11 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Christoph Hellwig <hch@....de>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Jeremy Kerr <jk@...abs.org>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Linux FS-devel Mailing List <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/8] binfmt_elf: open code copy_siginfo_to_user to
 kernelspace buffer

On Wed, Apr 15, 2020 at 9:45 AM Christoph Hellwig <hch@....de> wrote:
>
> On Tue, Apr 14, 2020 at 03:15:09PM +0200, Arnd Bergmann wrote:
> > I don't think you are changing the behavior here, but I still wonder if it
> > is in fact correct for x32: is in_x32_syscall() true here when dumping an
> > x32 compat elf process, or should this rather be set according to which
> > binfmt_elf copy is being used?
>
> The infrastructure could enable that, although it would require more
> arch hooks I think.

I was more interested in whether you can tell if it's currently broken
or not. If my feeling is right that the current code does the wrong thing
here, it would be good to at least put a FIXME comment in there.

> I'd rather keep it out of this series and to
> an interested party.  Then again x32 doesn't seem to have a whole lot
> of interested parties..

Fine with me. It's on my mental list of things that we want to kill off
eventually as soon as the remaining users stop replying to questions
about it.

In fact I should really turn that into a properly maintained list in
Documentation/... that contains any options that someone has
asked about removing in the past, along with the reasons for keeping
it around and a time at which we should ask about it again.

      Arnd