Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  igmp: Avoid zero delay when receiving odd mixture of IGMP queries
  netdev: make net_device_ops const
  bcm63xx: make ethtool_ops const
  usbnet: make ethtool_ops const
  net: Fix build with INET disabled.
  net: introduce netif_addr_lock_nested() and call if when appropriate
  net: correct lock name in dev_[uc/mc]_sync documentations.
  net: sk_update_clone is only used in net/core/sock.c
  8139cp: fix missing napi_gro_flush.
  pktgen: set correct max and min in pktgen_setup_inject()
  smsc911x: Unconditionally include linux/smscphy.h in smsc911x.h
  asix: fix infinite loop in rx_fixup()
  net: Default UDP and UNIX diag to 'n'.
  r6040: fix typo in use of MCR0 register bits
  net: fix sock_clone reference mismatch with tcp memcontrol

1 files changed, 14 insertions, 5 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 00d4fa27d3e687..d87aa3510c5e0a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -381,16 +381,25 @@ static void mem_cgroup_put(struct mem_cgroup *memcg);
 static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
 void sock_update_memcg(struct sock *sk)
 {
-	/* A socket spends its whole life in the same cgroup */
-	if (sk->sk_cgrp) {
-		WARN_ON(1);
-		return;
-	}
 	if (static_branch(&memcg_socket_limit_enabled)) {
 		struct mem_cgroup *memcg;
 
 		BUG_ON(!sk->sk_prot->proto_cgroup);
 
+		/* Socket cloning can throw us here with sk_cgrp already
+		 * filled. It won't however, necessarily happen from
+		 * process context. So the test for root memcg given
+		 * the current task's memcg won't help us in this case.
+		 *
+		 * Respecting the original socket's memcg is a better
+		 * decision in this case.
+		 */
+		if (sk->sk_cgrp) {
+			BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
+			mem_cgroup_get(sk->sk_cgrp->memcg);
+			return;
+		}
+
 		rcu_read_lock();
 		memcg = mem_cgroup_from_task(current);
 		if (!mem_cgroup_is_root(memcg)) {