Re: 32-bit PTI with THP = userspace corruption

[Linus Torvalds]

On Tue, Sep 11, 2018 at 1:49 AM Joerg Roedel <jroedel@xxxxxxx> wrote:
>
> I had a look into the THP and the HugeTLBfs code, and that is not
> really easy to fix there. As I can see it now, there are a few options
> to fix that, but most of them are ugly:

Just do (4): disable PTI with PAE.

Then we can try to make people perhaps not use !PAE very much, and
warn if you have PAE disabled on a machine that supports it.

As you say, there shouldn't be much of a performance impact from PAE.
There is a more noticeable performance impact from HIGHMEM, not from
HIGHMEM_64G, iirc.

                Linus