4 files changed, 60 insertions, 19 deletions

diff --git a/drivers/net/ovpn/tcp.c b/drivers/net/ovpn/tcp.c
index 289f62c5d2c7..0d7f30360d87 100644
--- a/drivers/net/ovpn/tcp.c
+++ b/drivers/net/ovpn/tcp.c
@@ -560,16 +560,34 @@ static void ovpn_tcp_close(struct sock *sk, long timeout)
 static __poll_t ovpn_tcp_poll(struct file *file, struct socket *sock,
 			      poll_table *wait)
 {
-	__poll_t mask = datagram_poll(file, sock, wait);
+	struct sk_buff_head *queue = &sock->sk->sk_receive_queue;
 	struct ovpn_socket *ovpn_sock;
+	struct ovpn_peer *peer = NULL;
+	__poll_t mask;
 
 	rcu_read_lock();
 	ovpn_sock = rcu_dereference_sk_user_data(sock->sk);
-	if (ovpn_sock && ovpn_sock->peer &&
-	    !skb_queue_empty(&ovpn_sock->peer->tcp.user_queue))
-		mask |= EPOLLIN | EPOLLRDNORM;
+	/* if we landed in this callback, we expect to have a
+	 * meaningful state. The ovpn_socket lifecycle would
+	 * prevent it otherwise.
+	 */
+	if (WARN(!ovpn_sock || !ovpn_sock->peer,
+		 "ovpn: null state in ovpn_tcp_poll!")) {
+		rcu_read_unlock();
+		return 0;
+	}
+
+	if (ovpn_peer_hold(ovpn_sock->peer)) {
+		peer = ovpn_sock->peer;
+		queue = &peer->tcp.user_queue;
+	}
 	rcu_read_unlock();
 
+	mask = datagram_poll_queue(file, sock, wait, queue);
+
+	if (peer)
+		ovpn_peer_put(peer);
+
 	return mask;
 }
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index fb3fec9affaa..a7cc3d1f4fd1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4204,6 +4204,9 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk,
 				    struct sk_buff_head *sk_queue,
 				    unsigned int flags, int *off, int *err);
 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags, int *err);
+__poll_t datagram_poll_queue(struct file *file, struct socket *sock,
+			     struct poll_table_struct *wait,
+			     struct sk_buff_head *rcv_queue);
 __poll_t datagram_poll(struct file *file, struct socket *sock,
 			   struct poll_table_struct *wait);
 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
diff --git a/net/core/datagram.c b/net/core/datagram.c
index cb4b9ef2e4e3..c285c6465923 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -920,21 +920,22 @@ fault:
 EXPORT_SYMBOL(skb_copy_and_csum_datagram_msg);
 
 /**
- * 	datagram_poll - generic datagram poll
+ *	datagram_poll_queue - same as datagram_poll, but on a specific receive
+ *		queue
  *	@file: file struct
  *	@sock: socket
  *	@wait: poll table
+ *	@rcv_queue: receive queue to poll
  *
- *	Datagram poll: Again totally generic. This also handles
- *	sequenced packet sockets providing the socket receive queue
- *	is only ever holding data ready to receive.
+ *	Performs polling on the given receive queue, handling shutdown, error,
+ *	and connection state. This is useful for protocols that deliver
+ *	userspace-bound packets through a custom queue instead of
+ *	sk->sk_receive_queue.
  *
- *	Note: when you *don't* use this routine for this protocol,
- *	and you use a different write policy from sock_writeable()
- *	then please supply your own write_space callback.
+ *	Return: poll bitmask indicating the socket's current state
  */
-__poll_t datagram_poll(struct file *file, struct socket *sock,
-			   poll_table *wait)
+__poll_t datagram_poll_queue(struct file *file, struct socket *sock,
+			     poll_table *wait, struct sk_buff_head *rcv_queue)
 {
 	struct sock *sk = sock->sk;
 	__poll_t mask;
@@ -956,7 +957,7 @@ __poll_t datagram_poll(struct file *file, struct socket *sock,
 		mask |= EPOLLHUP;
 
 	/* readable? */
-	if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
+	if (!skb_queue_empty_lockless(rcv_queue))
 		mask |= EPOLLIN | EPOLLRDNORM;
 
 	/* Connection-based need to check for termination and startup */
@@ -978,4 +979,27 @@ __poll_t datagram_poll(struct file *file, struct socket *sock,
 
 	return mask;
 }
+EXPORT_SYMBOL(datagram_poll_queue);
+
+/**
+ *	datagram_poll - generic datagram poll
+ *	@file: file struct
+ *	@sock: socket
+ *	@wait: poll table
+ *
+ *	Datagram poll: Again totally generic. This also handles
+ *	sequenced packet sockets providing the socket receive queue
+ *	is only ever holding data ready to receive.
+ *
+ *	Note: when you *don't* use this routine for this protocol,
+ *	and you use a different write policy from sock_writeable()
+ *	then please supply your own write_space callback.
+ *
+ *	Return: poll bitmask indicating the socket's current state
+ */
+__poll_t datagram_poll(struct file *file, struct socket *sock, poll_table *wait)
+{
+	return datagram_poll_queue(file, sock, wait,
+				   &sock->sk->sk_receive_queue);
+}
 EXPORT_SYMBOL(datagram_poll);
diff --git a/net/xfrm/espintcp.c b/net/xfrm/espintcp.c
index fc7a603b04f1..bf744ac9d5a7 100644
--- a/net/xfrm/espintcp.c
+++ b/net/xfrm/espintcp.c
@@ -555,14 +555,10 @@ static void espintcp_close(struct sock *sk, long timeout)
 static __poll_t espintcp_poll(struct file *file, struct socket *sock,
 			      poll_table *wait)
 {
-	__poll_t mask = datagram_poll(file, sock, wait);
 	struct sock *sk = sock->sk;
 	struct espintcp_ctx *ctx = espintcp_getctx(sk);
 
-	if (!skb_queue_empty(&ctx->ike_queue))
-		mask |= EPOLLIN | EPOLLRDNORM;
-
-	return mask;
+	return datagram_poll_queue(file, sock, wait, &ctx->ike_queue);
 }
 
 static void build_protos(struct proto *espintcp_prot,