Re: [PATCH 4/4] mm/slub: free KFENCE objects in slab_free_hook()

[Andrey Konovalov]

On Tue, Dec 12, 2023 at 12:42 PM Vlastimil Babka <vbabka@xxxxxxx> wrote:
>
> On 12/11/23 23:11, Andrey Konovalov wrote:
> > On Wed, Dec 6, 2023 at 3:45 PM Marco Elver <elver@xxxxxxxxxx> wrote:
> >>
> >> The is_kfence_address() implementation tolerates tagged addresses,
> >> i.e. if it receives a tagged non-kfence address, it will never return
> >> true.
>
> So just to be sure, it can't happen that a genuine kfence address would then
> become KASAN tagged and handed out, and thus when tested by
> is_kfence_address() it would be a false negative?

No, this should not happen. KFENCE objects never get tags assigned to them.