From 4219b2da206b3787dea4950ec53ccbc203f50e5e Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 23 Sep 2013 16:56:29 +0800 Subject: [PATCH] memcg: fail to create cgroup if the cgroup id is too big memcg requires the cgroup id to be smaller than 65536. This is a preparation to kill css id. Signed-off-by: Li Zefan Acked-by: Michal Hocko Signed-off-by: Tejun Heo --- mm/memcontrol.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 404a13a09efa..c14039575608 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -488,6 +488,12 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) return (memcg == root_mem_cgroup); } +/* + * We restrict the id in the range of [1, 65535], so it can fit into + * an unsigned short. + */ +#define MEM_CGROUP_ID_MAX USHRT_MAX + static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) { /* @@ -6059,6 +6065,9 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css) struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css)); int error = 0; + if (css->cgroup->id > MEM_CGROUP_ID_MAX) + return -ENOSPC; + if (!parent) return 0; -- GitLab