Re: [PATCH] mm: kmem: fix split_page_memcg()

From: Muchun Song
Date: Mon Aug 19 2024 - 22:38:05 EST




> On Aug 19, 2024, at 23:37, Shakeel Butt <shakeel.butt@xxxxxxxxx> wrote:
>
> On Mon, Aug 19, 2024 at 04:04:15PM GMT, Muchun Song wrote:
>> split_page_memcg() does not care about the returned memcg for kmem
>> pages, so folio_memcg_charged() should be used, otherwise obj_cgroup_memcg
>> will complain about this.
>
> Basically avoid calling folio_memcg() for folio_memcg_kmem(folio),
> correct?

Yes. Unless you hold rcu lock.

>
>>
>> Reported-by: syzbot+ef4ecf7b6bdc4157bfa4@xxxxxxxxxxxxxxxxxxxxxxxxx
>> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
>
> Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
>

Thanks.