Re: [PATCHv2] mm: Fix warning in move_normal_pmd()

[Linus Torvalds]

On Wed, Jul 15, 2020 at 2:35 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> The stack relocation only moves down.

.. and that may not be true on a grow-up stack. Christ, that code is
hard to read. But I think Kirill is right, and I'm wrong.

So that "try to expand" code is only ok when non-overlapping, or when
moving down.

Naresh - from a testing standpoint, that doesn't make any difference:
I'd still like you to test on x86. We always shift the stack down
there.

          Linus