mptcp: annotate lockless access for RX path fields

The following fields:

 - ack_seq
 - snd_una
 - wnd_end
 - rmem_fwd_alloc

are protected by the data lock end accessed lockless in a few
spots. Ensure ONCE annotation for write (under such lock) and for
lockless read.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 9b31a0a06265d55f25bc2063d27cd4dd10dd943a..801a3525230d010cb831de4fe9ff8e9a0c44cbb7 100644 (file)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1030,7 +1030,7 @@ u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq)
 static void __mptcp_snd_una_update(struct mptcp_sock *msk, u64 new_snd_una)
 {
        msk->bytes_acked += new_snd_una - msk->snd_una;
-       msk->snd_una = new_snd_una;
+       WRITE_ONCE(msk->snd_una, new_snd_una);
 }
 
 static void ack_update_msk(struct mptcp_sock *msk,
@@ -1057,7 +1057,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
        new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
 
        if (after64(new_wnd_end, msk->wnd_end))
-               msk->wnd_end = new_wnd_end;
+               WRITE_ONCE(msk->wnd_end, new_wnd_end);
 
        /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
        if (after64(msk->wnd_end, snd_nxt))
@@ -1071,7 +1071,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
 
        trace_ack_update_msk(mp_opt->data_ack,
                             old_snd_una, new_snd_una,
-                            new_wnd_end, msk->wnd_end);
+                            new_wnd_end, READ_ONCE(msk->wnd_end));
 }
 
 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index b1c24ac3630ffb2333330941a8ecf829e6c2880e..90804e7fb7f6f3fff3c4be00e8baf9de3b0a000b 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -410,6 +410,7 @@ static void mptcp_close_wake_up(struct sock *sk)
                sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
 }
 
+/* called under the msk socket lock */
 static bool mptcp_pending_data_fin_ack(struct sock *sk)
 {
        struct mptcp_sock *msk = mptcp_sk(sk);
@@ -441,16 +442,17 @@ static void mptcp_check_data_fin_ack(struct sock *sk)
        }
 }
 
+/* can be called with no lock acquired */
 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
 {
        struct mptcp_sock *msk = mptcp_sk(sk);
 
        if (READ_ONCE(msk->rcv_data_fin) &&
-           ((1 << sk->sk_state) &
+           ((1 << inet_sk_state_load(sk)) &
             (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
                u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
 
-               if (msk->ack_seq == rcv_data_fin_seq) {
+               if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {
                        if (seq)
                                *seq = rcv_data_fin_seq;
 
@@ -748,7 +750,7 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
                        __skb_queue_tail(&sk->sk_receive_queue, skb);
                }
                msk->bytes_received += end_seq - msk->ack_seq;
-               msk->ack_seq = end_seq;
+               WRITE_ONCE(msk->ack_seq, end_seq);
                moved = true;
        }
        return moved;
@@ -985,6 +987,7 @@ static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
        put_page(dfrag->page);
 }
 
+/* called under both the msk socket lock and the data lock */
 static void __mptcp_clean_una(struct sock *sk)
 {
        struct mptcp_sock *msk = mptcp_sk(sk);
@@ -2110,7 +2113,7 @@ static unsigned int mptcp_inq_hint(const struct sock *sk)
 
        skb = skb_peek(&msk->receive_queue);
        if (skb) {
-               u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
+               u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;
 
                if (hint_val >= INT_MAX)
                        return INT_MAX;
@@ -2754,7 +2757,7 @@ static void __mptcp_init_sock(struct sock *sk)
        __skb_queue_head_init(&msk->receive_queue);
        msk->out_of_order_queue = RB_ROOT;
        msk->first_pending = NULL;
-       msk->rmem_fwd_alloc = 0;
+       WRITE_ONCE(msk->rmem_fwd_alloc, 0);
        WRITE_ONCE(msk->rmem_released, 0);
        msk->timer_ival = TCP_RTO_MIN;
        msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
@@ -2970,7 +2973,7 @@ static void __mptcp_destroy_sock(struct sock *sk)
 
        sk->sk_prot->destroy(sk);
 
-       WARN_ON_ONCE(msk->rmem_fwd_alloc);
+       WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc));
        WARN_ON_ONCE(msk->rmem_released);
        sk_stream_kill_queues(sk);
        xfrm_sk_free_policy(sk);
@@ -3204,8 +3207,8 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 
        WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);
        WRITE_ONCE(msk->snd_nxt, msk->write_seq);
-       msk->snd_una = msk->write_seq;
-       msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
+       WRITE_ONCE(msk->snd_una, msk->write_seq);
+       WRITE_ONCE(msk->wnd_end, msk->snd_nxt + req->rsk_rcv_wnd);
        msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
        mptcp_init_sched(msk, mptcp_sk(sk)->sched);