linux-kernel - Re: [PATCH v1 2/8] mm, kasan: SLAB support

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Message-ID: <CAG_fn=V1VkfFmf3FO6KGSUxaXRsK-h9u7gtE-mSmXuESyg1o7g@mail.gmail.com>
Date:	Fri, 19 Feb 2016 13:57:09 +0100
From:	Alexander Potapenko <glider@...gle.com>
To:	Joonsoo Kim <js1304@...il.com>
Cc:	Joonsoo Kim <iamjoonsoo.kim@....com>, kasan-dev@...glegroups.com,
	Christoph Lameter <cl@...ux.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Dmitriy Vyukov <dvyukov@...gle.com>,
	Andrey Ryabinin <ryabinin.a.a@...il.com>,
	Linux Memory Management List <linux-mm@...ck.org>,
	Andrey Konovalov <adech.fo@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH v1 2/8] mm, kasan: SLAB support

Ah, yes, I see.
This patch was indeed missing the following bits in kasan_slab_free():

#ifdef CONFIG_SLAB
 if (cache->flags & SLAB_KASAN) {
 struct kasan_free_meta *free_info =
 get_free_info(cache, object);
 struct kasan_alloc_meta *alloc_info =
 get_alloc_info(cache, object);
 alloc_info->state = KASAN_STATE_FREE;
 set_track(&free_info->track);
 }
#endif

I'll include them in the next round of patches.

On Fri, Feb 19, 2016 at 2:41 AM, Joonsoo Kim <js1304@...il.com> wrote:
>> On Mon, Feb 1, 2016 at 3:15 AM, Joonsoo Kim <iamjoonsoo.kim@....com> wrote:
>>> On Thu, Jan 28, 2016 at 02:29:42PM +0100, Alexander Potapenko wrote:
>>>> On Thu, Jan 28, 2016 at 1:37 PM, Alexander Potapenko <glider@...gle.com> wrote:
>>>> >
>>>> > On Jan 28, 2016 8:44 AM, "Joonsoo Kim" <iamjoonsoo.kim@....com> wrote:
>>>> >>
>>>> >> On Wed, Jan 27, 2016 at 07:25:07PM +0100, Alexander Potapenko wrote:
>>>> >> > This patch adds KASAN hooks to SLAB allocator.
>>>> >> >
>>>> >> > This patch is based on the "mm: kasan: unified support for SLUB and
>>>> >> > SLAB allocators" patch originally prepared by Dmitry Chernenkov.
>>>> >> >
>>>> >> > Signed-off-by: Alexander Potapenko <glider@...gle.com>
>>>> >> > ---
>>>> >> >  Documentation/kasan.txt  |  5 ++-
>>>> >>
>>>> >> ...
>>>> >>
>>>> >> > +#ifdef CONFIG_SLAB
>>>> >> > +struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
>>>> >> > +                                     const void *object)
>>>> >> > +{
>>>> >> > +     return (void *)object + cache->kasan_info.alloc_meta_offset;
>>>> >> > +}
>>>> >> > +
>>>> >> > +struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
>>>> >> > +                                   const void *object)
>>>> >> > +{
>>>> >> > +     return (void *)object + cache->kasan_info.free_meta_offset;
>>>> >> > +}
>>>> >> > +#endif
>>>> >>
>>>> >> I cannot find the place to store stack info for free. get_free_info()
>>>> >> isn't used except print_object(). Plese let me know where.
>>>> >
>>>> > This is covered by other patches in this patchset.
>>>
>>> This should be covered by this patch. Stroing and printing free_info
>>> is already done on SLUB and it is meaningful without quarantain.
>
> 2016-02-18 21:58 GMT+09:00 Alexander Potapenko <glider@...gle.com>:
>> However this info is meaningless without saved stack traces, which are
>> only introduced in the stackdepot patch (see "[PATCH v1 5/8] mm,
>> kasan: Stackdepot implementation. Enable stackdepot for SLAB")
>
> Not meaningless. You already did it for allocation caller without saved
> stack traces. What makes difference between alloc/free?
>
> Thanks.



-- 
Alexander Potapenko
Software Engineer

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