SLAB_TYPESAFE_BY_RCU without constructors (was Re: [PATCH v4 13/17] khwasan: add hooks implementation)

[Dmitry Vyukov]

On Wed, Aug 1, 2018 at 12:23 PM, Eric Dumazet <eric.dumazet at gmail.com> wrote:
> On 08/01/2018 02:03 AM, Andrey Ryabinin wrote:
>
>> I can't think of any advantage in not having the constructor.
>
> I can't see any advantage adding another indirect call,
> in RETPOLINE world.

Can you please elaborate what's the problem here?
If slab ctor call have RETPOLINE, then using ctors more does not
introduce any security problems and they are not _that_ slow.
If slab ctors are not protected, then we have problem that needs to be
fixed already.
What am I missing?