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Date:   Thu, 30 Nov 2023 16:26:14 +0100
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Subject: Re: [PATCH v2 16/33] mm: slub: Let KMSAN access metadata
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To:     Ilya Leoshkevich <iii@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Marco Elver <elver@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Pekka Enberg <penberg@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vasily Gorbik <gor@linux.ibm.com>
Cc:     Christian Borntraeger <borntraeger@linux.ibm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-s390@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Sven Schnelle <svens@linux.ibm.com>
References: <20231121220155.1217090-1-iii@linux.ibm.com>
 <20231121220155.1217090-17-iii@linux.ibm.com>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20231121220155.1217090-17-iii@linux.ibm.com>
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On 11/21/23 23:01, Ilya Leoshkevich wrote:
> Building the kernel with CONFIG_SLUB_DEBUG and CONFIG_KMSAN causes
> KMSAN to complain about touching redzones in kfree().
> 
> Fix by extending the existing KASAN-related metadata_access_enable()
> and metadata_access_disable() functions to KMSAN.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>  mm/slub.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 169e5f645ea8..6e61c27951a4 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -700,10 +700,12 @@ static int disable_higher_order_debug;
>  static inline void metadata_access_enable(void)
>  {
>  	kasan_disable_current();
> +	kmsan_disable_current();
>  }
>  
>  static inline void metadata_access_disable(void)
>  {
> +	kmsan_enable_current();
>  	kasan_enable_current();
>  }
>