Re: [PATCH] x86: Deprecate a.out support

[Jann Horn]

On Tue, Mar 5, 2019 at 5:22 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Mar 5, 2019 at 6:59 AM Borislav Petkov <bp@xxxxxxxxx> wrote:
> > We can at least deprecate it on x86...
>
> I'd prefer to try to deprecate a.out core dumping first.. That's the
> part that is actually broken, no?
>
> In fact, I'd be happy to deprecate a.out entirely, but if somebody
> _does_ complain, I'd like to be able to bring it back without the core
> dumping.
>
> Because I think the likeliihood that anybody cares about a.out core
> dumps is basically zero. While the likelihood that we have some odd
> old binary that is still a.out is slightly above zero.
>
> So I'd be much happier with this if it was a two-stage thing where we
> just delete a.out core dumping entirely first, and then deprecate even
> running a.out binaries separately.
>
> Because I think all the known *bugs* we had were with the core dumping
> code, weren't they?
>
> Removing it looks trivial. Untested patch attached.

We might want to also delete the then-unused aout_dump_thread()
implementations from the various arch trees. We probably want to
delete arch/*/include/asm/a.out-core.h, since that seems to be the
only thing these headers do, and the only thing that uses them is
fs/binfmt_aout.c?