Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core)

[Linus Torvalds]

On Fri, Jun 24, 2016 at 10:21 AM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> But as mentioned, I must have missed something. There were a number of
> places where the code used the task_stack_page() and
> task_thread_info() interchangably, which used to work and is no longer
> true. There might simply be cases I missed.

.. and immediately as I wrote that, I went "Duh".

One place I missed was free_thread_info(), which should now free the
stack, not the ti pointer. But it does

        struct page *page = virt_to_page(ti);

and frees that, which is bogus. It turns out that we do do

        free_thread_info(tsk->stack);

which is bogus too, and undoes it, but I think I have a few new places
to look at..

                Linus