3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Hocko <mhocko@xxxxxxx> commit f37a96914d1aea10fed8d9af10251f0b9caea31b upstream. mem_cgroup_css_online calls mem_cgroup_put if memcg_init_kmem fails. This is not correct because only memcg_propagate_kmem takes an additional reference while mem_cgroup_sockets_init is allowed to fail as well (although no current implementation fails) but it doesn't take any reference. This all suggests that it should be memcg_propagate_kmem that should clean up after itself so this patch moves mem_cgroup_put over there. Unfortunately this is not that easy (as pointed out by Li Zefan) because memcg_kmem_mark_dead marks the group dead (KMEM_ACCOUNTED_DEAD) if it is marked active (KMEM_ACCOUNTED_ACTIVE) which is the case even if memcg_propagate_kmem fails so the additional reference is dropped in that case in kmem_cgroup_destroy which means that the reference would be dropped two times. The easiest way then would be to simply remove mem_cgrroup_put from mem_cgroup_css_online and rely on kmem_cgroup_destroy doing the right thing. Signed-off-by: Michal Hocko <mhocko@xxxxxxx> Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Glauber Costa <glommer@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 8 -------- 1 file changed, 8 deletions(-) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6296,14 +6296,6 @@ mem_cgroup_css_online(struct cgroup *con error = memcg_init_kmem(memcg, &mem_cgroup_subsys); mutex_unlock(&memcg_create_mutex); - if (error) { - /* - * We call put now because our (and parent's) refcnts - * are already in place. mem_cgroup_put() will internally - * call __mem_cgroup_free, so return directly - */ - mem_cgroup_put(memcg); - } return error; } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html