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Commit a03f1f05 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
Browse files

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: default avatarMichal Hocko <mhocko@suse.cz>
Reviewed-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9f2115f9

mm/memcontrol.c

+1 −2
Original line number Diff line number Diff line
@@ -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;

		}