From: Andrew Morton <akpm@linux-foundation.org>
To: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: Add additional consistency check
Date: Fri, 31 Mar 2017 14:33:17 -0700 [thread overview]
Message-ID: <20170331143317.3865149a6b6112f0d1a63499@linux-foundation.org> (raw)
In-Reply-To: <20170331164028.GA118828@beast>
On Fri, 31 Mar 2017 09:40:28 -0700 Kees Cook <keescook@chromium.org> wrote:
> As found in PaX, this adds a cheap check on heap consistency, just to
> notice if things have gotten corrupted in the page lookup.
"As found in PaX" isn't a very illuminating justification for such a
change. Was there a real kernel bug which this would have exposed, or
what?
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -384,6 +384,7 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
> return s;
>
> page = virt_to_head_page(x);
> + BUG_ON(!PageSlab(page));
> cachep = page->slab_cache;
> if (slab_equal_or_root(cachep, s))
> return cachep;
BUG_ON might be too severe. I expect the kindest VM_WARN_ON_ONCE()
would suffice here, but without more details it is hard to say.
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next prev parent reply other threads:[~2017-03-31 21:33 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-31 16:40 Kees Cook
2017-03-31 21:33 ` Andrew Morton [this message]
2017-04-01 0:04 ` Kees Cook
2017-04-03 3:40 ` Michael Ellerman
2017-04-03 14:03 ` Christoph Lameter
2017-04-03 14:53 ` Matthew Wilcox
2017-04-04 11:30 ` Michal Hocko
2017-04-04 15:07 ` Christoph Lameter
2017-04-04 15:16 ` Michal Hocko
2017-04-04 15:46 ` Kees Cook
2017-04-04 15:58 ` Michal Hocko
2017-04-04 16:02 ` Kees Cook
2017-04-04 19:13 ` Christoph Lameter
2017-04-04 19:42 ` Michal Hocko
2017-04-04 19:58 ` Christoph Lameter
2017-04-04 20:13 ` Michal Hocko
2017-04-11 4:58 ` Kees Cook
2017-04-11 13:46 ` Michal Hocko
2017-04-11 14:14 ` Kees Cook
2017-04-11 14:19 ` Michal Hocko
2017-04-11 16:05 ` Kees Cook
2017-04-11 16:16 ` Christoph Lameter
2017-04-11 16:19 ` Kees Cook
2017-04-11 16:23 ` Christoph Lameter
2017-04-11 16:30 ` Kees Cook
2017-04-11 16:26 ` Christoph Lameter
2017-04-11 16:41 ` Michal Hocko
2017-04-11 18:03 ` Christoph Lameter
2017-04-11 18:30 ` Michal Hocko
2017-04-11 18:44 ` Christoph Lameter
2017-04-11 18:55 ` Michal Hocko
2017-04-11 18:59 ` Christoph Lameter
2017-04-11 19:39 ` Michal Hocko
2017-04-17 15:22 ` Christoph Lameter
2017-04-18 6:41 ` Michal Hocko
2017-04-18 13:31 ` Christoph Lameter
2017-04-18 13:37 ` Christoph Lameter
2017-04-28 1:11 ` Kees Cook
2017-04-28 6:16 ` Michal Hocko
2017-04-27 12:06 ` Michal Hocko
2017-04-11 18:30 ` Christoph Lameter
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