Re: [PATCH] mm: memcg: initialize *locked in memcg1_oom_prepare() stub

[Joshua Hahn]

Hi Breno, I hope you are doing well : -)
Woah, thank you for finding and fixing this bug! 

> Fixes: e93d4166b40a ("mm: memcg: put cgroup v1-specific code under a config option")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
>  mm/memcontrol-v1.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h
> index f92f81108d5ed..4fa6e2bc8413f 100644
> --- a/mm/memcontrol-v1.h
> +++ b/mm/memcontrol-v1.h
> @@ -107,7 +107,11 @@ static inline void memcg1_remove_from_trees(struct mem_cgroup *memcg) {}
>  static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {}
>  static inline void memcg1_css_offline(struct mem_cgroup *memcg) {}
>  
> -static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) { return true; }
> +static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked)
> +{
> +	*locked = false;
> +	return true;
> +}
>  static inline void memcg1_oom_finish(struct mem_cgroup *memcg, bool locked) {}
>  static inline void memcg1_oom_recover(struct mem_cgroup *memcg) {}

Part of me wonders if we should just initialize locked = false in the
caller (mem_cgroup_oom) as to not make the stub have side effects,
but your chnage looks correct and this is a fix so perhaps that is
not so important.

Looks good to me! Thank you again Breno : -)

Reviewed-by: Joshua Hahn <joshua.hahnjy@xxxxxxxxx>