Re: [PATCH] mm/shrinker: avoid out-of-bounds read in set_shrinker_bit()

[Muchun Song]

> On May 11, 2026, at 02:37, David Carlier <devnexen@xxxxxxxxx> wrote:
> 
> set_shrinker_bit() reads info->unit[shrinker_id_to_index(shrinker_id)]
> before checking shrinker_id against info->map_nr_max, so an id past the
> currently visible map_nr_max reads past the unit[] array before the
> WARN_ON_ONCE() catches it.
> 
> Move the load into the bounded branch.
> 
> Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred}")
> Signed-off-by: David Carlier <devnexen@xxxxxxxxx>

Acked-by: Muchun Song <muchun.song@xxxxxxxxx>

Thanks.