Merge branch 'mptcp-fixes'

Matthieu Baerts says:

====================
mptcp: fixes for v6.2

Patch 1 clears resources earlier if there is no more reasons to keep
MPTCP sockets alive.

Patches 2 and 3 fix some locking issues visible in some rare corner
cases: the linked issues should be quite hard to reproduce.

Patch 4 makes sure subflows are correctly cleaned after the end of a
connection.

Patch 5 and 6 improve the selftests stability when running in a slow
environment by transfering data for a longer period on one hand and by
stopping the tests when all expected events have been observed on the
other hand.

All these patches fix issues introduced before v6.2.
====================
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/pm_netlink.c

@@ -998,8 +998,8 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 {
 	int addrlen = sizeof(struct sockaddr_in);
 	struct sockaddr_storage addr;
-	struct mptcp_sock *msk;
 	struct socket *ssock;
+	struct sock *newsk;
 	int backlog = 1024;
 	int err;
 
@@ -1008,11 +1008,13 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 	if (err)
 		return err;
 
-	msk = mptcp_sk(entry->lsk->sk);
-	if (!msk)
+	newsk = entry->lsk->sk;
+	if (!newsk)
 		return -EINVAL;
 
-	ssock = __mptcp_nmpc_socket(msk);
+	lock_sock(newsk);
+	ssock = __mptcp_nmpc_socket(mptcp_sk(newsk));
+	release_sock(newsk);
 	if (!ssock)
 		return -EINVAL;
 

net/mptcp/protocol.c

@@ -2897,6 +2897,7 @@ bool __mptcp_close(struct sock *sk, long timeout)
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	bool do_cancel_work = false;
+	int subflows_alive = 0;
 
 	sk->sk_shutdown = SHUTDOWN_MASK;
 
@@ -2922,6 +2923,8 @@ bool __mptcp_close(struct sock *sk, long timeout)
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 		bool slow = lock_sock_fast_nested(ssk);
 
+		subflows_alive += ssk->sk_state != TCP_CLOSE;
+
 		/* since the close timeout takes precedence on the fail one,
 		 * cancel the latter
 		 */
@@ -2937,6 +2940,12 @@ bool __mptcp_close(struct sock *sk, long timeout)
 	}
 	sock_orphan(sk);
 
+	/* all the subflows are closed, only timeout can change the msk
+	 * state, let's not keep resources busy for no reasons
+	 */
+	if (subflows_alive == 0)
+		inet_sk_state_store(sk, TCP_CLOSE);
+
 	sock_hold(sk);
 	pr_debug("msk=%p state=%d", sk, sk->sk_state);
 	if (msk->token)

net/mptcp/sockopt.c

@@ -760,14 +760,21 @@ static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname,
 static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
 					  sockptr_t optval, unsigned int optlen)
 {
+	struct sock *sk = (struct sock *)msk;
 	struct socket *sock;
+	int ret = -EINVAL;
 
 	/* Limit to first subflow, before the connection establishment */
+	lock_sock(sk);
 	sock = __mptcp_nmpc_socket(msk);
 	if (!sock)
-		return -EINVAL;
+		goto unlock;
 
-	return tcp_setsockopt(sock->sk, level, optname, optval, optlen);
+	ret = tcp_setsockopt(sock->sk, level, optname, optval, optlen);
+
+unlock:
+	release_sock(sk);
+	return ret;
 }
 
 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,

net/mptcp/subflow.c

@@ -1399,6 +1399,7 @@ void __mptcp_error_report(struct sock *sk)
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 		int err = sock_error(ssk);
+		int ssk_state;
 
 		if (!err)
 			continue;
@@ -1409,7 +1410,14 @@ void __mptcp_error_report(struct sock *sk)
 		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
 			continue;
 
-		inet_sk_state_store(sk, inet_sk_state_load(ssk));
+		/* We need to propagate only transition to CLOSE state.
+		 * Orphaned socket will see such state change via
+		 * subflow_sched_work_if_closed() and that path will properly
+		 * destroy the msk as needed.
+		 */
+		ssk_state = inet_sk_state_load(ssk);
+		if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
+			inet_sk_state_store(sk, ssk_state);
 		sk->sk_err = -err;
 
 		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
@@ -1679,7 +1687,7 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
 	if (err)
 		return err;
 
-	lock_sock(sf->sk);
+	lock_sock_nested(sf->sk, SINGLE_DEPTH_NESTING);
 
 	/* the newly created socket has to be in the same cgroup as its parent */
 	mptcp_attach_cgroup(sk, sf->sk);

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -498,6 +498,12 @@ kill_events_pids()
 	kill_wait $evts_ns2_pid
 }
 
+kill_tests_wait()
+{
+	kill -SIGUSR1 $(ip netns pids $ns2) $(ip netns pids $ns1)
+	wait
+}
+
 pm_nl_set_limits()
 {
 	local ns=$1
@@ -1694,6 +1700,7 @@ chk_subflow_nr()
 	local subflow_nr=$3
 	local cnt1
 	local cnt2
+	local dump_stats
 
 	if [ -n "${need_title}" ]; then
 		printf "%03u %-36s %s" "${TEST_COUNT}" "${TEST_NAME}" "${msg}"
@@ -1711,7 +1718,12 @@ chk_subflow_nr()
 		echo "[ ok ]"
 	fi
 
-	[ "${dump_stats}" = 1 ] && ( ss -N $ns1 -tOni ; ss -N $ns1 -tOni | grep token; ip -n $ns1 mptcp endpoint )
+	if [ "${dump_stats}" = 1 ]; then
+		ss -N $ns1 -tOni
+		ss -N $ns1 -tOni | grep token
+		ip -n $ns1 mptcp endpoint
+		dump_stats
+	fi
 }
 
 chk_link_usage()
@@ -3049,7 +3061,7 @@ endpoint_tests()
 		pm_nl_set_limits $ns1 2 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
-		run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow &
+		run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow 2>/dev/null &
 
 		wait_mpj $ns1
 		pm_nl_check_endpoint 1 "creation" \
@@ -3062,14 +3074,14 @@ endpoint_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 flags signal
 		pm_nl_check_endpoint 0 "modif is allowed" \
 			$ns2 10.0.2.2 id 1 flags signal
-		wait
+		kill_tests_wait
 	fi
 
 	if reset "delete and re-add"; then
 		pm_nl_set_limits $ns1 1 1
 		pm_nl_set_limits $ns2 1 1
 		pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow
-		run_tests $ns1 $ns2 10.0.1.1 4 0 0 slow &
+		run_tests $ns1 $ns2 10.0.1.1 4 0 0 speed_20 2>/dev/null &
 
 		wait_mpj $ns2
 		pm_nl_del_endpoint $ns2 2 10.0.2.2
@@ -3079,7 +3091,7 @@ endpoint_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 dev ns2eth2 flags subflow
 		wait_mpj $ns2
 		chk_subflow_nr "" "after re-add" 2
-		wait
+		kill_tests_wait
 	fi
 }