Re: [2/3] mm: fix up some user-visible effects of the stack guard page

From: Linus Torvalds
Date: Mon Jan 05 2015 - 16:11:25 EST


On Mon, Jan 5, 2015 at 1:03 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Yup, your analysis sounds correct. My completely untested gut feel is
> that the problem is that we don't actually return the error from the
> expand_stack() call, so then do_anonymous_page() will allow the extra
> guard-page access.
>
> IOW, *maybe* a patch like this. TOTALLY UNTESTED! I may have missed
> something, and this may be complete crap.

.. and ti's still untested, but I'm pretty sure it's right - except we
should probably also allow an extra page for the stack rlimit (so that
the guard page doesn't count towards the limit).

Linus
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