Re: [PATCH] x86_64: fixup TASK_SIZE_MAX comment

[Andy Lutomirski]

On Thu, Mar 5, 2020 at 10:17 AM Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
>
> Comment says "by preventing anything executable" which is not true.
> Even PROT_NONE mapping can't be installed at (1<<47 - 4096).
>
>         mmap(0x7ffffffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM

Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>

>
> I wonder if CPUs with wider address space carried the bugs...

I believe they do.  I won't swear to it.

FWIW, I specifically asked Intel to kindly fix this bug^Wfeature as
part of LA57, and I did not get a helpful response.