tcp/dccp: fix race at listener dismantle phase
Under stress, a close() on a listener can trigger the WARN_ON(sk->sk_ack_backlog) in inet_csk_listen_stop() We need to test if listener is still active before queueing a child in inet_csk_reqsk_queue_add() Create a common inet_child_forget() helper, and use it from inet_csk_reqsk_queue_add() and inet_csk_listen_stop() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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f03f2e154f
Коммит
ebb516af60
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@ -268,13 +268,8 @@ struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
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struct sock *newsk,
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const struct request_sock *req);
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static inline void inet_csk_reqsk_queue_add(struct sock *sk,
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struct request_sock *req,
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struct sock *child)
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{
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reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
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}
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void inet_csk_reqsk_queue_add(struct sock *sk, struct request_sock *req,
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struct sock *child);
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void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
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unsigned long timeout);
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@ -186,25 +186,6 @@ static inline bool reqsk_queue_empty(const struct request_sock_queue *queue)
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return queue->rskq_accept_head == NULL;
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}
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static inline void reqsk_queue_add(struct request_sock_queue *queue,
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struct request_sock *req,
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struct sock *parent,
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struct sock *child)
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{
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spin_lock(&queue->rskq_lock);
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req->sk = child;
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sk_acceptq_added(parent);
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if (queue->rskq_accept_head == NULL)
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queue->rskq_accept_head = req;
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else
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queue->rskq_accept_tail->dl_next = req;
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queue->rskq_accept_tail = req;
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req->dl_next = NULL;
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spin_unlock(&queue->rskq_lock);
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}
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static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue,
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struct sock *parent)
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{
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@ -764,6 +764,53 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
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}
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EXPORT_SYMBOL_GPL(inet_csk_listen_start);
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static void inet_child_forget(struct sock *sk, struct request_sock *req,
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struct sock *child)
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{
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sk->sk_prot->disconnect(child, O_NONBLOCK);
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sock_orphan(child);
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percpu_counter_inc(sk->sk_prot->orphan_count);
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if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
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BUG_ON(tcp_sk(child)->fastopen_rsk != req);
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BUG_ON(sk != req->rsk_listener);
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/* Paranoid, to prevent race condition if
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* an inbound pkt destined for child is
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* blocked by sock lock in tcp_v4_rcv().
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* Also to satisfy an assertion in
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* tcp_v4_destroy_sock().
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*/
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tcp_sk(child)->fastopen_rsk = NULL;
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}
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inet_csk_destroy_sock(child);
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reqsk_put(req);
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}
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void inet_csk_reqsk_queue_add(struct sock *sk, struct request_sock *req,
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struct sock *child)
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{
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struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
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spin_lock(&queue->rskq_lock);
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if (unlikely(sk->sk_state != TCP_LISTEN)) {
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inet_child_forget(sk, req, child);
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} else {
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req->sk = child;
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req->dl_next = NULL;
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if (queue->rskq_accept_head == NULL)
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queue->rskq_accept_head = req;
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else
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queue->rskq_accept_tail->dl_next = req;
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queue->rskq_accept_tail = req;
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sk_acceptq_added(sk);
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}
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spin_unlock(&queue->rskq_lock);
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}
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EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
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/*
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* This routine closes sockets which have been at least partially
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* opened, but not yet accepted.
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@ -790,31 +837,11 @@ void inet_csk_listen_stop(struct sock *sk)
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WARN_ON(sock_owned_by_user(child));
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sock_hold(child);
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sk->sk_prot->disconnect(child, O_NONBLOCK);
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sock_orphan(child);
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percpu_counter_inc(sk->sk_prot->orphan_count);
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if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
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BUG_ON(tcp_sk(child)->fastopen_rsk != req);
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BUG_ON(sk != req->rsk_listener);
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/* Paranoid, to prevent race condition if
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* an inbound pkt destined for child is
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* blocked by sock lock in tcp_v4_rcv().
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* Also to satisfy an assertion in
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* tcp_v4_destroy_sock().
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*/
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tcp_sk(child)->fastopen_rsk = NULL;
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}
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inet_csk_destroy_sock(child);
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inet_child_forget(sk, req, child);
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bh_unlock_sock(child);
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local_bh_enable();
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sock_put(child);
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reqsk_put(req);
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cond_resched();
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}
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if (queue->fastopenq.rskq_rst_head) {
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@ -829,7 +856,7 @@ void inet_csk_listen_stop(struct sock *sk)
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req = next;
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}
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}
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WARN_ON(sk->sk_ack_backlog);
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WARN_ON_ONCE(sk->sk_ack_backlog);
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}
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EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
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