2023-11-21 22:04:13

by Ilya Leoshkevich

Subject: [PATCH v2 16/33] mm: slub: Let KMSAN access metadata

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 <[email protected]>
---
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

2023-11-30 15:26:35

by Vlastimil Babka

Subject: Re: [PATCH v2 16/33] mm: slub: Let KMSAN access metadata

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 <[email protected]>

Acked-by: Vlastimil Babka <[email protected]>

> ---
> 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();
> }
>