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From: Kees Cook <keescook@chromium.org>
To: Qian Cai <cai@lca.pw>
Cc: akpm@linux-foundation.org, glider@google.com, cl@linux.com,
	penberg@kernel.org, rientjes@google.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] slub: play init_on_free=1 well with SLAB_RED_ZONE
Date: Thu, 20 Jun 2019 18:19:27 -0700	[thread overview]
Message-ID: <201906201818.6C90BC875@keescook> (raw)
In-Reply-To: <201906201812.8B49A36@keescook>

On Thu, Jun 20, 2019 at 06:14:33PM -0700, Kees Cook wrote:
> On Thu, Jun 20, 2019 at 03:28:01PM -0400, Qian Cai wrote:
> > diff --git a/mm/slub.c b/mm/slub.c
> > index a384228ff6d3..787971d4fa36 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -1437,7 +1437,7 @@ static inline bool slab_free_freelist_hook(struct kmem_cache *s,
> >  		do {
> >  			object = next;
> >  			next = get_freepointer(s, object);
> > -			memset(object, 0, s->size);
> > +			memset(object, 0, s->object_size);
> 
> I think this should be more dynamic -- we _do_ want to wipe all
> of object_size in the case where it's just alignment and padding
> adjustments. If redzones are enabled, let's remove that portion only.

(Sorry, I meant: all of object's "size", not object_size.)

-- 
Kees Cook


  reply	other threads:[~2019-06-21  1:19 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-20 19:28 Qian Cai
2019-06-21  1:14 ` Kees Cook
2019-06-21  1:19   ` Kees Cook [this message]
2019-06-21 12:55     ` Qian Cai
2019-06-25 16:16       ` Alexander Potapenko

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