Commit 099ecf59 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: annotate lockless accesses to sk->sk_max_ack_backlog 



sk->sk_max_ack_backlog can be read without any lock being held
at least in TCP/DCCP cases.

We need to use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing
and/or potential KCSAN warnings.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 288efe86

include/net/sock.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -869,7 +869,7 @@ static inline void sk_acceptq_added(struct sock *sk) 




static inline bool sk_acceptq_is_full(const struct sock *sk)

static inline bool sk_acceptq_is_full(const struct sock *sk)

{

{

	return READ_ONCE(sk->sk_ack_backlog) > sk->sk_max_ack_backlog;

	return READ_ONCE(sk->sk_ack_backlog) > READ_ONCE(sk->sk_max_ack_backlog);

}

}





/*

/*

net/dccp/proto.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -944,7 +944,7 @@ int inet_dccp_listen(struct socket *sock, int backlog) 
	if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))

	if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))

		goto out;

		goto out;





	sk->sk_max_ack_backlog = backlog;

	WRITE_ONCE(sk->sk_max_ack_backlog, backlog);

	/* Really, if the socket is already in listen state

	/* Really, if the socket is already in listen state

	 * we can only allow the backlog to be adjusted.

	 * we can only allow the backlog to be adjusted.

	 */

	 */

net/ipv4/af_inet.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -208,7 +208,7 @@ int inet_listen(struct socket *sock, int backlog) 
	if (!((1 << old_state) & (TCPF_CLOSE | TCPF_LISTEN)))

	if (!((1 << old_state) & (TCPF_CLOSE | TCPF_LISTEN)))

		goto out;

		goto out;





	sk->sk_max_ack_backlog = backlog;

	WRITE_ONCE(sk->sk_max_ack_backlog, backlog);

	/* Really, if the socket is already in listen state

	/* Really, if the socket is already in listen state

	 * we can only allow the backlog to be adjusted.

	 * we can only allow the backlog to be adjusted.

	 */

	 */

net/ipv4/inet_connection_sock.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -716,7 +716,7 @@ static void reqsk_timer_handler(struct timer_list *t) 
	 * ones are about to clog our table.

	 * ones are about to clog our table.

	 */

	 */

	qlen = reqsk_queue_len(queue);

	qlen = reqsk_queue_len(queue);

	if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {

	if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {

		int young = reqsk_queue_len_young(queue) << 1;

		int young = reqsk_queue_len_young(queue) << 1;





		while (thresh > 2) {

		while (thresh > 2) {

net/ipv4/tcp.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -3226,7 +3226,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) 
		 * tcpi_sacked  -> max backlog

		 * tcpi_sacked  -> max backlog

		 */

		 */

		info->tcpi_unacked = READ_ONCE(sk->sk_ack_backlog);

		info->tcpi_unacked = READ_ONCE(sk->sk_ack_backlog);

		info->tcpi_sacked = sk->sk_max_ack_backlog;

		info->tcpi_sacked = READ_ONCE(sk->sk_max_ack_backlog);

		return;

		return;

	}

	}

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