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>
---
 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();
 }
 
-- 
2.41.0

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();
>  }
>