Re: [patch 0/5] Support for sanitization flag in low-level page allocator

Ingo Molnar
2009-05-27T22:34:01Z

* Rik van Riel <riel@redhat.com> wrote:

> Ingo Molnar wrote:
>
>> What you are missing is that your patch makes _no technical
>> sense_ if you allow the same information to leak over the kernel
>> stack. Kernel stacks can be freed and reused, swapped out and
>> thus 'exposed'.
>
> Kernel stacks may be freed and reused, but Larry's latest patch
> takes care of that by clearing them at page free time.
>
> As for being swapped out - I do not believe that kernel stacks can
> ever be swapped out in Linux.

yes, i referred to that as an undesirable option - because it slows
down pthread_create() quite substantially.

This needs before/after pthread_create() benchmark results.

Ingo