linux-kernel - Re: [PATCH v2] mm/slub: support left redzone

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Date:	Fri, 26 Feb 2016 19:47:48 +0300
From:	Andrey Ryabinin <ryabinin.a.a@...il.com>
To:	js1304@...il.com
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: Re: [PATCH v2] mm/slub: support left redzone

2016-02-26 7:36 GMT+03:00  <js1304@...il.com>:
> From: Joonsoo Kim <iamjoonsoo.kim@....com>
>
> SLUB already has a redzone debugging feature.  But it is only positioned
> at the end of object (aka right redzone) so it cannot catch left oob.
> Although current object's right redzone acts as left redzone of next
> object, first object in a slab cannot take advantage of this effect.  This
> patch explicitly adds a left red zone to each object to detect left oob
> more precisely.
>

So why for each object? Can't we have left redzone only for the first object?