diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f60f01b14fac4..12bb28c5007ed 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3294,6 +3294,17 @@ static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v) return 0; delta = msk->write_seq - v; + if (__mptcp_check_fallback(msk) && msk->first) { + struct tcp_sock *tp = tcp_sk(msk->first); + + /* the first subflow is disconnected after close - see + * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq + * so ignore that status, too. + */ + if (!((1 << msk->first->sk_state) & + (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))) + delta += READ_ONCE(tp->write_seq) - tp->snd_una; + } if (delta > INT_MAX) delta = INT_MAX;