From: Paolo Abeni pabeni@redhat.com

If the peer closes all the existing subflows for a given mptcp socket and later the application closes it, the current implementation let it survive until the timewait timeout expires.

While the above is allowed by the protocol specification it consumes resources for almost no reason and additionally causes sporadic self-tests failures.

Let's move the mptcp socket to the TCP_CLOSE state when there are no alive subflows at close time, so that the allocated resources will be freed immediately.

Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net --- net/mptcp/protocol.c | 9 +++++++++ 1 file changed, 9 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 8cd6cc67c2c5..bc6c1f62a690 100644 --- a/net/mptcp/protocol.c +++ b/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)

From: Paolo Abeni pabeni@redhat.com

For consistency, in mptcp_pm_nl_create_listen_socket(), we need to call the __mptcp_nmpc_socket() under the msk socket lock.

Note that as a side effect, mptcp_subflow_create_socket() needs a 'nested' lockdep annotation, as it will acquire the subflow (kernel) socket lock under the in-kernel listener msk socket lock.

The current lack of locking is almost harmless, because the relevant socket is not exposed to the user space, but in future we will add more complexity to the mentioned helper, let's play safe.

Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net --- net/mptcp/pm_netlink.c | 10 ++++++---- net/mptcp/subflow.c | 2 +- 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 2ea7eae43bdb..10fe9771a852 100644 --- a/net/mptcp/pm_netlink.c +++ b/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;

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index ec54413fb31f..a3e5026bee5b 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1679,7 +1679,7 @@ 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);

From: Paolo Abeni pabeni@redhat.com

A test-case is frequently failing on some extremely slow VMs. The mptcp transfer completes before the script is able to do all the required PM manipulation.

Address the issue in the simplest possible way, making the transfer even more slow.

Additionally dump more info in case of failures, to help debugging similar problems in the future and init dump_stats var.

Fixes: e274f7154008 ("selftests: mptcp: add subflow limits test-cases") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/323 Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net --- tools/testing/selftests/net/mptcp/mptcp_join.sh | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh index d11d3d566608..f8a969300ef4 100755 --- a/tools/testing/selftests/net/mptcp/mptcp_join.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh @@ -1694,6 +1694,7 @@ 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 +1712,12 @@ 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() @@ -3069,7 +3075,7 @@ endpoint_tests() 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 &

wait_mpj $ns2 pm_nl_del_endpoint $ns2 2 10.0.2.2