Re: [PATCH] mm: Make copy_huge_page() always available

From: Matthew Wilcox
Date: Tue Jul 13 2021 - 22:22:50 EST


On Tue, Jul 13, 2021 at 07:12:44PM -0700, Andrew Morton wrote:
> On Mon, 12 Jul 2021 16:32:07 +0100 "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> wrote:
>
> > Rewrite copy_huge_page() and move it into mm/util.c so it's always
> > available. Fixes an exposure of uninitialised memory on configurations
> > with HUGETLB and UFFD enabled and MIGRATION disabled.
>
> Wait. Exposing uninitialized memory is serious. Can we please include
> full info on this flaw and decide whether a -stable backport is justified?
> If not, why not, etc?

Well, the code was only merged this merge window, so as long as it goes
in in the next few weeks, there's no need to trouble -stable with it.