On Fri,  7 Jul 2017 10:34:08 +0200 Alexander Potapenko <gli...@google.com> 
wrote:

> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3389,8 +3389,8 @@ static int init_kmem_cache_nodes(struct kmem_cache *s)
>                       return 0;
>               }
>  
> -             s->node[node] = n;
>               init_kmem_cache_node(n);
> +             s->node[node] = n;
>       }
>       return 1;
>  }

If this matters then I have bad feelings about free_kmem_cache_nodes():

static void free_kmem_cache_nodes(struct kmem_cache *s)
{
        int node;
        struct kmem_cache_node *n;

        for_each_kmem_cache_node(s, node, n) {
                kmem_cache_free(kmem_cache_node, n);
                s->node[node] = NULL;
        }
}

Inviting a use-after-free?  I guess not, as there should be no way
to look up these items at this stage.

Could the slab maintainers please take a look at these and also have a
think about Alexander's READ_ONCE/WRITE_ONCE question?

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