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Date: Tue, 18 Apr 2017 08:37:13 -0500 (CDT)
From: Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH] mm: Add additional consistency check
In-Reply-To: <20170418064124.GA22360@dhcp22.suse.cz>
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References: <20170411141956.GP6729@dhcp22.suse.cz> <alpine.DEB.2.20.1704111110130.24725@east.gentwo.org> <20170411164134.GA21171@dhcp22.suse.cz> <alpine.DEB.2.20.1704111254390.25069@east.gentwo.org> <20170411183035.GD21171@dhcp22.suse.cz>
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Sender: owner-linux-mm@kvack.org
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To: Michal Hocko <mhocko@kernel.org>
Cc: Kees Cook <keescook@chromium.org>, Andrew Morton <akpm@linux-foundation.org>, Pekka Enberg <penberg@kernel.org>, David Rientjes <rientjes@google.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>

On Tue, 18 Apr 2017, Michal Hocko wrote:

> Are you even reading those emails? First of all we are talking about
> slab here. Secondly I've already pointed out that the BUG_ON(!PageSlab)
> in kmem_freepages is already too late because we do operate on a
> potential garbage from invalid page...

Before I forget:

1. The patch affects both slab and slub since it patches mm/slab.h and is
called by both allocators.

2. The check in the patch we are discussing here when calling
kmem_cache_free() will be executing before kmem_freepages() is called
in slab.

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