From: Vasily Averin <vvs@xxxxxxxxxxxxx> Subject: mm/memcontrol.c: lost css_put in memcg_expand_shrinker_maps() for_each_mem_cgroup() increases css reference counter for memory cgroup and requires to use mem_cgroup_iter_break() if the walk is cancelled. Link: http://lkml.kernel.org/r/c98414fb-7e1f-da0f-867a-9340ec4bd30b@xxxxxxxxxxxxx Fixes: 0a4465d34028 ("mm, memcg: assign memcg-aware shrinkers bitmap to memcg") Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx> Acked-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Roman Gushchin <guro@xxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/memcontrol.c~memcg-lost-css_put-in-memcg_expand_shrinker_maps +++ a/mm/memcontrol.c @@ -409,8 +409,10 @@ int memcg_expand_shrinker_maps(int new_i if (mem_cgroup_is_root(memcg)) continue; ret = memcg_expand_one_shrinker_map(memcg, size, old_size); - if (ret) + if (ret) { + mem_cgroup_iter_break(NULL, memcg); goto unlock; + } } unlock: if (!ret) _
