Re: [RFC][PATCH 13/24] x86/pti: Extend PTI user mappings

[Andy Lutomirski]

On Mon, Nov 9, 2020 at 3:22 AM Alexandre Chartre
<alexandre.chartre@xxxxxxxxxx> wrote:
>
> Extend PTI user mappings so that more kernel entry code can be executed
> with the user page-table. To do so, we need to map syscall and interrupt
> entry code,

Probably fine.

> per cpu offsets (__per_cpu_offset, which is used some in
> entry code),

This likely already leaks due to vulnerable CPUs leaking address space
layout info.

> the stack canary,

That's going to be a very tough sell.