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Date: Tue, 4 Apr 2017 17:58:56 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Pekka Enberg <penberg@kernel.org>,
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        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Linux-MM <linux-mm@kvack.org>,
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Subject: Re: [PATCH] mm: Add additional consistency check
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On Tue 04-04-17 08:46:02, Kees Cook wrote:
> On Tue, Apr 4, 2017 at 8:16 AM, Michal Hocko <mhocko@kernel.org> wrote:
> > On Tue 04-04-17 10:07:23, Cristopher Lameter wrote:
> >> On Tue, 4 Apr 2017, Michal Hocko wrote:
> >>
> >> > NAK without a proper changelog. Seriously, we do not blindly apply
> >> > changes from other projects without a deep understanding of all
> >> > consequences.
> >>
> >> Functionalitywise this is trivial. A page must be a slab page in order to
> >> be able to determine the slab cache of an object. Its definitely not ok if
> >> the page is not a slab page.
> >
> > Yes, but we do not have to blow the kernel, right? Why cannot we simply
> > leak that memory?
> 
> I can put this behind CHECK_DATA_CORRUPTION() instead of BUG(), which
> allows the system builder to choose between WARN and BUG. Some people
> absolutely want the kernel to BUG on data corruption as it could be an
> attack.

CHECK_DATA_CORRUPTION sounds as better fit to me. This would, however
require to handle the potenial corruption by returning and leaking the
memory.

-- 
Michal Hocko
SUSE Labs