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authorMichal Hocko <mhocko@suse.cz>2015-09-08 15:01:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-08 15:35:28 -0700
commita03f1f058969ec350fb7451a6fbca23096ee5727 (patch)
treeb6745897f8969fe99a4a514b9d76eaaa167ff84d /mm/memcontrol.c
parent9f2115f93b88e5e8d48b87b153e36a537afb58cb (diff)
memcg, tcp_kmem: check for cg_proto in sock_update_memcg
sk_prot->proto_cgroup is allowed to return NULL but sock_update_memcg doesn't check for NULL. The function relies on the mem_cgroup_is_root check because we shouldn't get NULL otherwise because mem_cgroup_from_task will always return !NULL. All other callers are checking for NULL and we can safely replace mem_cgroup_is_root() check by cg_proto != NULL which will be more straightforward (proto_cgroup returns NULL for the root memcg already). Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 191d8aa5da71..3033e6c42229 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -315,8 +315,7 @@ void sock_update_memcg(struct sock *sk)
rcu_read_lock();
memcg = mem_cgroup_from_task(current);
cg_proto = sk->sk_prot->proto_cgroup(memcg);
- if (!mem_cgroup_is_root(memcg) &&
- memcg_proto_active(cg_proto) &&
+ if (cg_proto && memcg_proto_active(cg_proto) &&
css_tryget_online(&memcg->css)) {
sk->sk_cgrp = cg_proto;
}