Re: [PATCH 2/3] memcgroup: fix typo in VM_BUG_ON()

[yamamoto@valinux.co.jp (YAMAMOTO Takashi)]

> No need for VM_BUG_ON(pc), since 'pc' is the list entry. This should
> be VM_BUG_ON(page).
> 
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
>  mm/memcontrol.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6bded84..c2959ee 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -534,7 +534,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
>  		if (scan >= nr_to_scan)
>  			break;
>  		page = pc->page;
> -		VM_BUG_ON(!pc);
> +		VM_BUG_ON(!page);

can't page be NULL here if mem_cgroup_uncharge clears pc->page behind us?
ie. bug.

YAMAMOTO Takashi