Re: [PATCH] mm: memcontrol: Fix do not put the css reference

[Roman Gushchin]

On Sun, Jun 14, 2020 at 08:26:53PM +0800, Muchun Song wrote:
> We should put the css reference when memory allocation failed.
> 
> Fixes: f0a3a24b532d ("mm: memcg/slab: rework non-root kmem_cache lifecycle management")
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> ---
>  mm/memcontrol.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Good catch, thank you!

Acked-by: Roman Gushchin <guro@xxxxxx>

> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 0b38b6ad547d..2323d811ee8e 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2772,8 +2772,10 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
>  		return;
>  
>  	cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
> -	if (!cw)
> +	if (!cw) {
> +		css_put(&memcg->css);
>  		return;
> +	}
>  
>  	cw->memcg = memcg;
>  	cw->cachep = cachep;
> -- 
> 2.11.0
>