Re: [RFC PATCH 1/2] x86/ibpb: Skip IBPB when we switch back to same user process

[Andy Lutomirski]

On Thu, Jan 25, 2018 at 1:57 PM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
> Andy Lutomirski <luto@xxxxxxxxxx> writes:
>>
>> That being said, just stashing last_user_mm without any refcounting
>> should be fine.
>
> If last_user_mm is freed and reallocated by a different process,
> then that would miss the IPBP incorrectly.
>

Hmm, right.  So ctx_id it is.

--Andy