Re: [PATCH -mm 2/8] memcg: keep all children of each root cache on a list

Vladimir Davydov
2014-07-07T15:45:55Z

On Mon, Jul 07, 2014 at 10:24:35AM -0500, Christoph Lameter wrote:
> On Mon, 7 Jul 2014, Vladimir Davydov wrote:
>
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > index d31c4bacc6a2..95a8f772b0d1 100644
> > --- a/mm/slab_common.c
> > +++ b/mm/slab_common.c
> > @@ -294,8 +294,12 @@ struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
> > if (IS_ERR(s)) {
> > kfree(cache_name);
> > s = NULL;
> > + goto out_unlock;
> > }
> >
> > + list_add(&s->memcg_params->siblings,
> > + &root_cache->memcg_params->children);
> > +
> > out_unlock:
> > mutex_unlock(&slab_mutex);
> >
>
> If there is an error then s is set to NULL. And then
> the list_add is done dereferencing s?

No, we skip list_add on error. I think you missed "goto out_unlock"
right after "s = NULL" (btw do_kmem_cache_create never returns NULL).

Thanks.