net: add netns refcount tracker to struct sock

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/sock.h

@@ -350,6 +350,7 @@ struct bpf_local_storage;
   *	@sk_txtime_deadline_mode: set deadline mode for SO_TXTIME
   *	@sk_txtime_report_errors: set report errors mode for SO_TXTIME
   *	@sk_txtime_unused: unused txtime flags
+  *	@ns_tracker: tracker for netns reference
   */
 struct sock {
 	/*
@@ -538,6 +539,7 @@ struct sock {
 	struct bpf_local_storage __rcu	*sk_bpf_storage;
 #endif
 	struct rcu_head		sk_rcu;
+	netns_tracker		ns_tracker;
 };
 
 enum sk_pacing {

net/core/sock.c

@@ -1983,7 +1983,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
 		sock_lock_init(sk);
 		sk->sk_net_refcnt = kern ? 0 : 1;
 		if (likely(sk->sk_net_refcnt)) {
-			get_net(net);
+			get_net_track(net, &sk->ns_tracker, priority);
 			sock_inuse_add(net, 1);
 		}
 
@@ -2039,7 +2039,7 @@ static void __sk_destruct(struct rcu_head *head)
 	put_pid(sk->sk_peer_pid);
 
 	if (likely(sk->sk_net_refcnt))
-		put_net(sock_net(sk));
+		put_net_track(sock_net(sk), &sk->ns_tracker);
 	sk_prot_free(sk->sk_prot_creator, sk);
 }
 
@@ -2126,7 +2126,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
 
 	/* SANITY */
 	if (likely(newsk->sk_net_refcnt)) {
-		get_net(sock_net(newsk));
+		get_net_track(sock_net(newsk), &newsk->ns_tracker, priority);
 		sock_inuse_add(sock_net(newsk), 1);
 	}
 	sk_node_init(&newsk->sk_node);