linux-kernel - Re: [PATCH] mm/slab: Do not hash pointers when debugging slab

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Message-ID: <CAGXu5j+9qWBM3G1ZtBXPi35UGkcfXnSbgZCBjXJM35X9+hS4ug@mail.gmail.com>
Date:   Thu, 7 Dec 2017 10:43:09 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Christopher Lameter <cl@...ux.com>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Tobin C . Harding" <me@...in.cc>, Linux-MM <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] mm/slab: Do not hash pointers when debugging slab

On Thu, Dec 7, 2017 at 3:13 AM, Christopher Lameter <cl@...ux.com> wrote:
> On Thu, 7 Dec 2017, Geert Uytterhoeven wrote:
>
>> If CONFIG_DEBUG_SLAB/CONFIG_DEBUG_SLAB_LEAK are enabled, the slab code
>> prints extra debug information when e.g. corruption is detected.
>> This includes pointers, which are not very useful when hashed.
>>
>> Fix this by using %px to print unhashed pointers instead.
>
> Acked-by: Christoph Lameter <cl@...ux.com>
>
> These SLAB config options are only used for testing so this is ok.

Most systems use SLUB so I can't say how common CONFIG_DEBUG_SLAB is.
(Though, FWIW with SLUB, CONFIG_SLUB_DEBUG is very common.)

-Kees

-- 
Kees Cook
Pixel Security