Re: [PATCH] pkeys: Introduce PKEY_ALLOC_SIGNALINHERIT and change signal semantics

[Dave Hansen <dave.hansen@intel.com>]

On 05/02/2018 06:14 PM, Andy Lutomirski wrote:
>> I think you are saying: If a thread calls pkey_alloc(), all
>> threads should, by default, implicitly get access.
> No, I’m saying that all threads should get the *requested* access.
> If I’m protecting the GOT, I want all threads to get RO access. If
> I’m writing a crypto library, I probably want all threads to have no
> access.  If I’m writing a database, I probably want all threads to
> get RO by default.  If I’m writing some doodad to sandbox some
> carefully constructed code, I might want all threads to have full
> access by default.

OK, fair enough.  I totally agree that the current interface (or
architecture for that matter) is not amenable to use models where we are
implicitly imposing policies on *other* threads.

I don't think that means the current stuff is broken for
multi-threading, though, just the (admittedly useful) cases you are
talking about where you want to poke at a remote thread's PKRU.

So, where do we go from here?