On 7/5/23 14:44, andrey.konovalov@linux.dev wrote:
From: Andrey Konovalov andreyknvl@google.com
Commit 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated kmalloc space than requested") added precise kmalloc redzone poisoning to the slub_debug functionality.
However, this commit didn't account for HW_TAGS KASAN fully initializing the object via its built-in memory initialization feature. Even though HW_TAGS KASAN memory initialization contains special memory initialization handling for when slub_debug is enabled, it does not account for in-object slub_debug redzones. As a result, HW_TAGS KASAN can overwrite these redzones and cause false-positive slub_debug reports.
To fix the issue, avoid HW_TAGS KASAN memory initialization when slub_debug is enabled altogether. Implement this by moving the __slub_debug_enabled check to slab_post_alloc_hook. Common slab code seems like a more appropriate place for a slub_debug check anyway.
Fixes: 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated kmalloc space than requested") Cc: stable@vger.kernel.org Reported-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Andrey Konovalov andreyknvl@google.com
Acked-by: Vlastimil Babka vbabka@suse.cz
Thanks!