Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 12 Oct 2020 08:01:04 +0000 (UTC)
From:   Christopher Lameter <cl@linux.com>
To:     Kees Cook <keescook@chromium.org>
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
In-Reply-To: <20201009195411.4018141-3-keescook@chromium.org>
Message-ID: <alpine.DEB.2.22.394.2010120754010.150059@www.lameter.com>
References: <20201009195411.4018141-1-keescook@chromium.org> <20201009195411.4018141-3-keescook@chromium.org>
User-Agent: Alpine 2.22 (DEB 394 2020-01-19)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Precedence: bulk

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.

NAK.