Date: Thu, 7 Dec 2017 14:15:27 -0600 (CST)
From: Christopher Lameter <cl@linux.com>
To: Kees Cook <keescook@chromium.org>
cc: Geert Uytterhoeven <geert+renesas@glider.be>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Tobin C . Harding" <me@tobin.cc>, Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] mm/slab: Do not hash pointers when debugging slab
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On Thu, 7 Dec 2017, Kees Cook wrote:

> > 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.)

CONFIG_SLUB_DEBUG is on by default because it compiles into the kernel the
runtime configurable debugging framework. It does not activate any
debugging.

CONFIG_SLUB_DEBUG_ON is the equivalent to CONFIG_SLAB_DEBUG. The kernel
will boot with debugging on without any extra kernel options with these.