Re: WARNING: CPU: 0 PID: 11655 at mm/page_counter.c:62

[Andrei Vagin <avagin@gmail.com>]

On Wed, Jun 19, 2019 at 2:19 PM Roman Gushchin <guro@fb.com> wrote:
>
> On Tue, Jun 18, 2019 at 07:08:26PM -0700, Andrei Vagin wrote:
> > Hello,
> >
> > We run CRIU tests on linux-next kernels and today we found this
> > warning in the kernel log:
>
> Hello, Andrei!
>
> Can you, please, check if the following patch fixes the problem?

All my tests passed: https://travis-ci.org/avagin/linux/builds/547940031

Tested-by: Andrei Vagin <avagin@gmail.com>

Thanks,
Andrei

>
> Thanks a lot!
>
> --
>
> diff --git a/mm/slab.h b/mm/slab.h
> index a4c9b9d042de..7667dddb6492 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -326,7 +326,8 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order,
>         memcg = READ_ONCE(s->memcg_params.memcg);
>         lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg);
>         mod_lruvec_state(lruvec, cache_vmstat_idx(s), -(1 << order));
> -       memcg_kmem_uncharge_memcg(page, order, memcg);
> +       if (!mem_cgroup_is_root(memcg))
> +               memcg_kmem_uncharge_memcg(page, order, memcg);
>         rcu_read_unlock();
>
>         percpu_ref_put_many(&s->memcg_params.refcnt, 1 << order);
>