diff options
Diffstat (limited to 'net/mptcp/protocol.c')
| -rw-r--r-- | net/mptcp/protocol.c | 42 |
1 files changed, 27 insertions, 15 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 8959a74f707d..35bdfb4f3eae 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1266,8 +1266,12 @@ static void mptcp_close(struct sock *sk, long timeout) mptcp_token_destroy(msk->token); inet_sk_state_store(sk, TCP_CLOSE); - __mptcp_flush_join_list(msk); - + /* be sure to always acquire the join list lock, to sync vs + * mptcp_finish_join(). + */ + spin_lock_bh(&msk->join_list_lock); + list_splice_tail_init(&msk->join_list, &msk->conn_list); + spin_unlock_bh(&msk->join_list_lock); list_splice_init(&msk->conn_list, &conn_list); data_fin_tx_seq = msk->write_seq; @@ -1623,22 +1627,30 @@ bool mptcp_finish_join(struct sock *sk) if (!msk->pm.server_side) return true; - /* passive connection, attach to msk socket */ + if (!mptcp_pm_allow_new_subflow(msk)) + return false; + + /* active connections are already on conn_list, and we can't acquire + * msk lock here. + * use the join list lock as synchronization point and double-check + * msk status to avoid racing with mptcp_close() + */ + spin_lock_bh(&msk->join_list_lock); + ret = inet_sk_state_load(parent) == TCP_ESTABLISHED; + if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) + list_add_tail(&subflow->node, &msk->join_list); + spin_unlock_bh(&msk->join_list_lock); + if (!ret) + return false; + + /* attach to msk socket only after we are sure he will deal with us + * at close time + */ parent_sock = READ_ONCE(parent->sk_socket); if (parent_sock && !sk->sk_socket) mptcp_sock_graft(sk, parent_sock); - - ret = mptcp_pm_allow_new_subflow(msk); - if (ret) { - subflow->map_seq = msk->ack_seq; - - /* active connections are already on conn_list */ - spin_lock_bh(&msk->join_list_lock); - if (!WARN_ON_ONCE(!list_empty(&subflow->node))) - list_add_tail(&subflow->node, &msk->join_list); - spin_unlock_bh(&msk->join_list_lock); - } - return ret; + subflow->map_seq = msk->ack_seq; + return true; } bool mptcp_sk_is_subflow(const struct sock *sk) |