From: Feng Tang <feng.tang@intel.com>
To: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Jonathan Corbet <corbet@lwn.net>,
"Hansen, Dave" <dave.hansen@intel.com>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
"Sang, Oliver" <oliver.sang@intel.com>
Subject: Re: [PATCH v5 3/4] mm: kasan: Add free_meta size info in struct kasan_cache
Date: Sun, 11 Sep 2022 11:56:24 +0800 [thread overview]
Message-ID: <Yx1caGQ8R2alhOKh@feng-clx> (raw)
In-Reply-To: <CA+fCnZeT_mYndXDYoi0LHCcDkOK4V1TR_omE6CKdbMf6iDwP+w@mail.gmail.com>
Hi Andrey,
Thanks for reviewing this series!
On Sun, Sep 11, 2022 at 07:14:55AM +0800, Andrey Konovalov wrote:
> On Wed, Sep 7, 2022 at 9:11 AM Feng Tang <feng.tang@intel.com> wrote:
> >
> > When kasan is enabled for slab/slub, it may save kasan' free_meta
> > data in the former part of slab object data area in slab object
> > free path, which works fine.
> >
> > There is ongoing effort to extend slub's debug function which will
> > redzone the latter part of kmalloc object area, and when both of
> > the debug are enabled, there is possible conflict, especially when
> > the kmalloc object has small size, as caught by 0Day bot [1]
> >
> > For better information for slab/slub, add free_meta's data size
> > into 'struct kasan_cache', so that its users can take right action
> > to avoid data conflict.
> >
> > [1]. https://lore.kernel.org/lkml/YuYm3dWwpZwH58Hu@xsang-OptiPlex-9020/
> > Reported-by: kernel test robot <oliver.sang@intel.com>
> > Signed-off-by: Feng Tang <feng.tang@intel.com>
> > Acked-by: Dmitry Vyukov <dvyukov@google.com>
> > ---
> > include/linux/kasan.h | 2 ++
> > mm/kasan/common.c | 2 ++
> > 2 files changed, 4 insertions(+)
> >
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index b092277bf48d..293bdaa0ba09 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -100,6 +100,8 @@ static inline bool kasan_has_integrated_init(void)
> > struct kasan_cache {
> > int alloc_meta_offset;
> > int free_meta_offset;
> > + /* size of free_meta data saved in object's data area */
> > + int free_meta_size_in_object;
>
> I thinks calling this field free_meta_size is clear enough. Thanks!
Yes, the name does look long. The "in_object" was added to make it
also a flag for whether the free meta is saved inside object's data
area.
For 'free_meta_size', the code logic in slub should be:
if (info->free_meta_offset == 0 &&
info->free_meta_size >= ...)
Thanks,
Feng
next prev parent reply other threads:[~2022-09-11 3:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 7:10 [PATCH v5 0/4] mm/slub: some debug enhancements for kmalloc Feng Tang
2022-09-07 7:10 ` [PATCH v5 1/4] mm/slub: enable debugging memory wasting of kmalloc Feng Tang
2022-09-07 14:17 ` Hyeonggon Yoo
2022-09-08 2:25 ` Feng Tang
2022-09-07 7:10 ` [PATCH v5 2/4] mm/slub: only zero the requested size of buffer for kzalloc Feng Tang
2022-09-07 14:57 ` Hyeonggon Yoo
2022-09-08 7:38 ` Feng Tang
2022-09-10 23:11 ` Andrey Konovalov
2022-09-11 5:04 ` Feng Tang
2022-09-07 7:10 ` [PATCH v5 3/4] mm: kasan: Add free_meta size info in struct kasan_cache Feng Tang
2022-09-10 23:14 ` Andrey Konovalov
2022-09-11 3:56 ` Feng Tang [this message]
2022-09-11 11:51 ` Andrey Konovalov
2022-09-11 12:29 ` Feng Tang
2022-09-07 7:10 ` [PATCH v5 4/4] mm/slub: extend redzone check to extra allocated kmalloc space than requested Feng Tang
2022-09-09 6:26 ` Hyeonggon Yoo
2022-09-09 7:33 ` Feng Tang
2022-09-10 23:12 ` Andrey Konovalov
2022-09-11 4:10 ` Feng Tang
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