From: Paolo Abeni pabeni@redhat.com
commit 81c1d029016001f994ce1c46849c5e9900d8eab8 upstream.
An orphaned msk releases the used resources via the worker, when the latter first see the msk in CLOSED status.
If the msk status transitions to TCP_CLOSE in the release callback invoked by the worker's final release_sock(), such instance of the workqueue will not take any action.
Additionally the MPTCP code prevents scheduling the worker once the socket reaches the CLOSE status: such msk resources will be leaked.
The only code path that can trigger the above scenario is the __mptcp_check_send_data_fin() in fallback mode.
Address the issue removing the special handling of fallback socket in __mptcp_check_send_data_fin(), consolidating the state machine for fallback and non fallback socket.
Since non-fallback sockets do not send and do not receive data_fin, the mptcp code can update the msk internal status to match the next step in the SM every time data fin (ack) should be generated or received.
As a consequence we can remove a bunch of checks for fallback from the fastpath.
Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 39 +++++++++++++++------------------------ net/mptcp/subflow.c | 17 ++++++++++------- 2 files changed, 25 insertions(+), 31 deletions(-)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -51,7 +51,7 @@ enum { static struct percpu_counter mptcp_sockets_allocated;
static void __mptcp_destroy_sock(struct sock *sk); -static void __mptcp_check_send_data_fin(struct sock *sk); +static void mptcp_check_send_data_fin(struct sock *sk);
DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); static struct net_device mptcp_napi_dev; @@ -355,8 +355,7 @@ static bool mptcp_pending_data_fin_ack(s { struct mptcp_sock *msk = mptcp_sk(sk);
- return !__mptcp_check_fallback(msk) && - ((1 << sk->sk_state) & + return ((1 << sk->sk_state) & (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && msk->write_seq == READ_ONCE(msk->snd_una); } @@ -509,9 +508,6 @@ static bool mptcp_check_data_fin(struct u64 rcv_data_fin_seq; bool ret = false;
- if (__mptcp_check_fallback(msk)) - return ret; - /* Need to ack a DATA_FIN received from a peer while this side * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. * msk->rcv_data_fin was set when parsing the incoming options @@ -549,7 +545,8 @@ static bool mptcp_check_data_fin(struct }
ret = true; - mptcp_send_ack(msk); + if (!__mptcp_check_fallback(msk)) + mptcp_send_ack(msk); mptcp_close_wake_up(sk); } return ret; @@ -1612,7 +1609,7 @@ out: if (!mptcp_timer_pending(sk)) mptcp_reset_timer(sk); if (copied) - __mptcp_check_send_data_fin(sk); + mptcp_check_send_data_fin(sk); }
static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk) @@ -2451,7 +2448,6 @@ static void mptcp_worker(struct work_str if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN))) goto unlock;
- mptcp_check_data_fin_ack(sk); mptcp_flush_join_list(msk);
mptcp_check_fastclose(msk); @@ -2462,7 +2458,8 @@ static void mptcp_worker(struct work_str if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) mptcp_check_for_eof(msk);
- __mptcp_check_send_data_fin(sk); + mptcp_check_send_data_fin(sk); + mptcp_check_data_fin_ack(sk); mptcp_check_data_fin(sk);
/* There is no point in keeping around an orphaned sk timedout or @@ -2591,6 +2588,12 @@ void mptcp_subflow_shutdown(struct sock pr_debug("Fallback"); ssk->sk_shutdown |= how; tcp_shutdown(ssk, how); + + /* simulate the data_fin ack reception to let the state + * machine move forward + */ + WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt); + mptcp_schedule_work(sk); } else { pr_debug("Sending DATA_FIN on subflow %p", ssk); tcp_send_ack(ssk); @@ -2630,7 +2633,7 @@ static int mptcp_close_state(struct sock return next & TCP_ACTION_FIN; }
-static void __mptcp_check_send_data_fin(struct sock *sk) +static void mptcp_check_send_data_fin(struct sock *sk) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); @@ -2648,18 +2651,6 @@ static void __mptcp_check_send_data_fin(
WRITE_ONCE(msk->snd_nxt, msk->write_seq);
- /* fallback socket will not get data_fin/ack, can move to the next - * state now - */ - if (__mptcp_check_fallback(msk)) { - if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) { - inet_sk_state_store(sk, TCP_CLOSE); - mptcp_close_wake_up(sk); - } else if (sk->sk_state == TCP_FIN_WAIT1) { - inet_sk_state_store(sk, TCP_FIN_WAIT2); - } - } - mptcp_flush_join_list(msk); mptcp_for_each_subflow(msk, subflow) { struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); @@ -2680,7 +2671,7 @@ static void __mptcp_wr_shutdown(struct s WRITE_ONCE(msk->write_seq, msk->write_seq + 1); WRITE_ONCE(msk->snd_data_fin_enable, 1);
- __mptcp_check_send_data_fin(sk); + mptcp_check_send_data_fin(sk); }
static void __mptcp_destroy_sock(struct sock *sk) --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1653,14 +1653,16 @@ static void subflow_state_change(struct { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); struct sock *parent = subflow->conn; + struct mptcp_sock *msk;
__subflow_state_change(sk);
+ msk = mptcp_sk(parent); if (subflow_simultaneous_connect(sk)) { mptcp_propagate_sndbuf(parent, sk); mptcp_do_fallback(sk); - mptcp_rcv_space_init(mptcp_sk(parent), sk); - pr_fallback(mptcp_sk(parent)); + mptcp_rcv_space_init(msk, sk); + pr_fallback(msk); subflow->conn_finished = 1; mptcp_set_connected(parent); } @@ -1676,11 +1678,12 @@ static void subflow_state_change(struct
subflow_sched_work_if_closed(mptcp_sk(parent), sk);
- if (__mptcp_check_fallback(mptcp_sk(parent)) && - !subflow->rx_eof && subflow_is_done(sk)) { - subflow->rx_eof = 1; - mptcp_subflow_eof(parent); - } + /* when the fallback subflow closes the rx side, trigger a 'dummy' + * ingress data fin, so that the msk state will follow along + */ + if (__mptcp_check_fallback(msk) && subflow_is_done(sk) && msk->first == sk && + mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true)) + mptcp_schedule_work(parent); }
static int subflow_ulp_init(struct sock *sk)