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Date:   Mon, 12 Oct 2020 13:43:31 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Christopher Lameter <cl@linux.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, stable@vger.kernel.org,
        Marco Elver <elver@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Vlastimil Babka <vbabka@suse.cz>, Roman Gushchin <guro@fb.com>,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [PATCH v2 2/3] mm/slub: Fix redzoning for small allocations
Message-ID: <202010121342.836D3C26CF@keescook>
References: <20201009195411.4018141-1-keescook@chromium.org>
 <20201009195411.4018141-3-keescook@chromium.org>
 <alpine.DEB.2.22.394.2010120754010.150059@www.lameter.com>
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On Mon, Oct 12, 2020 at 08:01:04AM +0000, Christopher Lameter wrote:
> On Fri, 9 Oct 2020, Kees Cook wrote:
> 
> > Store the freelist pointer out of line when object_size is smaller than
> > sizeof(void *) and redzoning is enabled.
> >
> > (Note that no caches with such a size are known to exist in the kernel
> > currently.)
> 
> Ummm... The smallest allowable cache size is sizeof(void *) as I recall.
> 
> 
> mm/slab_common.c::kmem_sanity_check() checks the sizes when caches are
> created.

Ah thank you! Yes, I really thought there was a place where that
happened, but I missed it. This patch can be dropped.

-- 
Kees Cook