Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 16 Aug 2022 21:27:39 +0800
From:   Oliver Sang <oliver.sang@intel.com>
To:     Feng Tang <feng.tang@intel.com>
CC:     Dmitry Vyukov <dvyukov@google.com>,
        Vlastimil Babka <vbabka@suse.cz>, lkp <lkp@intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "lkp@lists.01.org" <lkp@lists.01.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        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>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        Robin Murphy <robin.murphy@arm.com>,
        John Garry <john.garry@huawei.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        "Alexander Potapenko" <glider@google.com>,
        "kasan-dev@googlegroups.com" <kasan-dev@googlegroups.com>
Subject: Re: [mm/slub] 3616799128:
 BUG_kmalloc-#(Not_tainted):kmalloc_Redzone_overwritten
Message-ID: <YvubS48W0dE7uA4E@xsang-OptiPlex-9020>
References: <YujKCxu2lJJFm73P@feng-skl>
 <CACT4Y+Zwg8BP=6WJpQ5cCbJxLu4HcnCjx8e53aDEbTZ5uzpUyg@mail.gmail.com>
 <85ec4ea8-ae4c-3592-5491-3db6d0ad8c59@suse.cz>
 <CACT4Y+asjzrBu8ogRDt9hYYaAB3tZ2pK5HBkzkuMp106vQwKWQ@mail.gmail.com>
 <YukoZEm4Q6CSEKKj@feng-skl>
 <CACT4Y+Y6M5MqSGC0MERFqkxgKYK+LrMYvW5xPH5kUA2mFh5_Xw@mail.gmail.com>
 <YutnCD5dPie/yoIk@feng-clx>
 <CACT4Y+Zzzj7+LwUwyMoBketXFBHRksnx148B1aLATZ48AU9o3w@mail.gmail.com>
 <Yuu6B0vUuXvtEG8b@feng-clx>
 <Yvn1b8y20Mr0gfUQ@feng-clx>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <Yvn1b8y20Mr0gfUQ@feng-clx>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?k+W4Rx/hcpgOkk5ndvRPUPf/OiYap1ry3O39wBrwbN2/KtUJ/LEh3fcd0D45?=
 =?us-ascii?Q?xl3+6LiOe5u8b6oGtmuaAyGRKB3rxrQUjPkw592m7tQ8ot/0/0Cq/bpFOITc?=
 =?us-ascii?Q?rUtitcsqCvIrev6TYnGVFU/A04Oc7JhNMA1in85v3cjI7IrOiFjufRVzEsxw?=
 =?us-ascii?Q?6G5JLwtyri06dVvVkz0sGWcejXZMGqiNbs9qbbID/71ypXimSRBPb0jUCnO4?=
 =?us-ascii?Q?Oh9Foc+diT4++ABaexmoHDwOEeClABv4fZRkOH6QufKhUvJtWee0SVRF5o//?=
 =?us-ascii?Q?3/wBfOHOB1rVkMlt/JX30nRO7zLyA79FDBKRiyep4GsN4zmYStI5LbyQu0XM?=
 =?us-ascii?Q?yIUWSq8YCyHmG8prr3v6COGFEQrJQKvKpp5jG4xGvvlLAiw6sZwLPX4f9eSO?=
 =?us-ascii?Q?bFd60cdb5zIKCd2q01wn6r2fFR8vDOFJG3oou87KR0pxHqmCC6+8qfFpSLxu?=
 =?us-ascii?Q?XdTdoQ+bs5L804MmdVzlLf3wZ7vggUQE+zjAaI/2jfRMIJd/FN+bC/0RF85v?=
 =?us-ascii?Q?J+qt+UcAfcS1bjvYOHO6WgYAoUv3Muvr3Zu0tG3zz8/RJBxH8U1sVtMH0bDp?=
 =?us-ascii?Q?sz68wrmlCkprRAO49cMA0YnpHVJxNIUFhyHyAE4kqgWX4eXj8s+ZX6pAI1FT?=
 =?us-ascii?Q?+Q7VrF1AYOxHHikD/Rdc/iIdHWE01hswpWTKAOVPXDpKcniamzSbbYCSfNlv?=
 =?us-ascii?Q?xB+cA1E/vW9StIMKgcyyNvZJm9UZ5v2X29nJK4AFM1uY4+bm7asI6rocN6Un?=
 =?us-ascii?Q?j6lKe6hDXd8gvMYotd9MRpIFFWLg3ftBtaNMV3VYFE+HKHKKyorIEeEaqIcm?=
 =?us-ascii?Q?8UJZp8CtqDABSSPnJnuojEqxM+t8q8LAbseDrXuAv23NCcuvUwV9lEbpDYdr?=
 =?us-ascii?Q?3V/CACGmT/M4UuJthT0rbgmAHJEOhBuvtC84wjROSfOHTzF4JnJ0YAEAmqJd?=
 =?us-ascii?Q?qd888XAr1DQoN7D2SxJZIiwuYovXyYAixGoT/mrr3iSKHtzy5ToI12Y6W74A?=
 =?us-ascii?Q?1LxeXu46Dv92iYzsIk5A+RrCp+k4ZwbtLG6hNRzk+pqvx2k+K3HLgFfO/TpW?=
 =?us-ascii?Q?yfT1hjwqFZSDwDfUdlM0vXFC6g9uegRroa7svoM8nud6XTH5aVsqcBAGAMhV?=
 =?us-ascii?Q?FPrENUy2qq+nhzncEbSD+jeGOZKL5bx2RTaDcXgeScQMv2fWaqUe6Ur+5eWT?=
 =?us-ascii?Q?S6vocIvHYyPThJOgjkbEUU7Z5PLLESC9fQ1IkqXHjoUcCGernlg6sIOv/6dj?=
 =?us-ascii?Q?NafUGuzwEcozJS5V/lJYrMC76l95j1/JEraGfQp5yQL/o9Z7CqSQs3QZAcgt?=
 =?us-ascii?Q?UR/SwsX45iUw1lXFjmxYOpREsw8mn8IehWNd7Y9KJL1JPIKdaOmlcNwkdh9D?=
 =?us-ascii?Q?T4PTxyQRXR4ugQYOdBJ9ly39RiLFKKq7IhZZiN6gzzVXCUzqBEqh4YbX/vXd?=
 =?us-ascii?Q?vlSo2p1yaKwIATUBKL0hvwlaKlcOoPm0aQF3QZ+pqSVeYJgR+30GxhTIPtr6?=
 =?us-ascii?Q?8MzHuy5hU8ASurQJNZFlW/v0cciQDtDo7BgvjK/SOM5WTHUZ+iO4tEBuM9CO?=
 =?us-ascii?Q?1c587EwR/KawmppPuDOv1lEaYSSVfwqFRVEoz5Z7ORs110eonSh1hEF3PzNj?=
 =?us-ascii?Q?Mw=3D=3D?=
X-MS-Exchange-CrossTenant-Network-Message-Id: d48c2c7a-678d-4d50-539a-08da7f8b2002
X-MS-Exchange-CrossTenant-AuthSource: SJ1PR11MB6297.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Aug 2022 13:27:54.4457
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: A1ua8xa0C+voX+SF1hvTrN9mcxAWt6Hf45g2UVxAh6pLvH0yAL4oEGFr1920KmrhjexUDjpnKwpUZW+BBTk1sQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR11MB2716
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham
        autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Feng,

On Mon, Aug 15, 2022 at 03:27:43PM +0800, Feng Tang wrote:
> Hi Oliver,
> 
> Could you help to check if the below combined patch fix the problem
> you reported? thanks!

I applied below patch upon 3616799128:
28b34693c816e9 (linux-devel/fixup-3616799128) fix for 3616799128: BUG_kmalloc-#(Not_tainted):kmalloc_Redzone_overwritten
3616799128612e (linux-review/Feng-Tang/mm-slub-some-debug-enhancements/20220727-151318) mm/slub: extend redzone check to cover extra allocated kmalloc space than requested
acc77d62f91ccc mm/slub: only zero the requested size of buffer for kzalloc


confirmed the issue gone:

=========================================================================================
compiler/kconfig/rootfs/sleep/tbox_group/testcase:
  gcc-11/x86_64-randconfig-a005-20220117/debian-11.1-x86_64-20220510.cgz/300/vm-snb/boot


acc77d62f91ccca2 3616799128612e04ed919579e2c 28b34693c816e9fcbe42bdd341e
---------------- --------------------------- ---------------------------
       fail:runs  %reproduction    fail:runs  %reproduction    fail:runs
           |             |             |             |             |
           :20          95%          19:20           0%            :22    dmesg.BUG_kmalloc-#(Not_tainted):kmalloc_Redzone_overwritten
           :20          95%          19:20           0%            :22    dmesg.BUG_kmalloc-#(Tainted:G_B):kmalloc_Redzone_overwritten


> 
> - Feng
> 
> ---
> 
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index b092277bf48d6..293bdaa0ba09c 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;
>  	bool is_kmalloc;
>  };
>  
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index c40c0e7b3b5f1..9d2994dbe4e7a 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -200,6 +200,8 @@ void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
>  			cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
>  			*size = ok_size;
>  		}
> +	} else {
> +		cache->kasan_info.free_meta_size_in_object = sizeof(struct kasan_free_meta);
>  	}
>  
>  	/* Calculate size with optimal redzone. */
> diff --git a/mm/slub.c b/mm/slub.c
> index added2653bb03..272dcdbaaa03b 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -830,6 +830,16 @@ static inline void set_orig_size(struct kmem_cache *s,
>  	if (!slub_debug_orig_size(s))
>  		return;
>  
> +#ifdef CONFIG_KASAN_GENERIC
> +	/*
> +	 * kasn could save its free meta data in the start part of object
> +	 * area, so skip the redzone check if kasan's meta data size is
> +	 * bigger enough to possibly overlap with kmalloc redzone
> +	 */
> +	if (s->kasan_info.free_meta_size_in_object * 2 > s->object_size)
> +		orig_size = s->object_size;
> +#endif
> +
>  	p += get_info_end(s);
>  	p += sizeof(struct track) * 2;
>  
> On Thu, Aug 04, 2022 at 08:22:31PM +0800, Tang, Feng wrote:
> > On Thu, Aug 04, 2022 at 06:47:58PM +0800, Dmitry Vyukov wrote:
> > >  On Thu, 4 Aug 2022 at 08:29, Feng Tang <feng.tang@intel.com> wrote:
> > [...]
> > > >
> > > > ---8<---
> > > > From c4fc739ea4d5222f0aba4b42b59668d64a010082 Mon Sep 17 00:00:00 2001
> > > > From: Feng Tang <feng.tang@intel.com>
> > > > Date: Thu, 4 Aug 2022 13:25:35 +0800
> > > > Subject: [PATCH] mm: kasan: Add free_meta size info in struct kasan_cache
> > > >
> > > > 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
> > > > info '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>
> >  
> > Thanks for your suggestion and review!
> > 
> > > I assume there will be a second patch that uses
> > > free_meta_size_in_object  in slub debug code.
> >  
> > Yes, it will be called in the slub kmalloc object redzone debug code.
> > 
> > Thanks,
> > Feng
> > 
> > > > ---
> > > >  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;
> > > >         bool is_kmalloc;
> > > >  };
> > > >
> > > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> > > > index 78be2beb7453..a627efa267d1 100644
> > > > --- a/mm/kasan/common.c
> > > > +++ b/mm/kasan/common.c
> > > > @@ -201,6 +201,8 @@ void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
> > > >                         cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
> > > >                         *size = ok_size;
> > > >                 }
> > > > +       } else {
> > > > +               cache->kasan_info.free_meta_size_in_object = sizeof(struct kasan_free_meta);
> > > >         }
> > > >
> > > >         /* Calculate size with optimal redzone. */
> > > > --
> > > > 2.27.0
> > >