Commit 3a037f0f authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: annotate data-races around icsk->icsk_syn_retries 



do_tcp_getsockopt() and reqsk_timer_handler() read
icsk->icsk_syn_retries while another cpu might change its value.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230719212857.3943972-7-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 6e5e1de6

net/ipv4/inet_connection_sock.c

+1 −1
Original line number Diff line number Diff line
@@ -1019,7 +1019,7 @@ static void reqsk_timer_handler(struct timer_list *t) 


	icsk = inet_csk(sk_listener);

	net = sock_net(sk_listener);

	max_syn_ack_retries = icsk->icsk_syn_retries ? :

	max_syn_ack_retries = READ_ONCE(icsk->icsk_syn_retries) ? :

		READ_ONCE(net->ipv4.sysctl_tcp_synack_retries);

	/* Normally all the openreqs are young and become mature

	 * (i.e. converted to established socket) for first timeout.

net/ipv4/tcp.c

+3 −3
Original line number Diff line number Diff line
@@ -3291,7 +3291,7 @@ int tcp_sock_set_syncnt(struct sock *sk, int val) 
		return -EINVAL;



	lock_sock(sk);

	inet_csk(sk)->icsk_syn_retries = val;

	WRITE_ONCE(inet_csk(sk)->icsk_syn_retries, val);

	release_sock(sk);

	return 0;

}
@@ -3572,7 +3572,7 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname, 
		if (val < 1 || val > MAX_TCP_SYNCNT)

			err = -EINVAL;

		else

			icsk->icsk_syn_retries = val;

			WRITE_ONCE(icsk->icsk_syn_retries, val);

		break;



	case TCP_SAVE_SYN:
@@ -3993,7 +3993,7 @@ int do_tcp_getsockopt(struct sock *sk, int level, 
		val = keepalive_probes(tp);

		break;

	case TCP_SYNCNT:

		val = icsk->icsk_syn_retries ? :

		val = READ_ONCE(icsk->icsk_syn_retries) ? :

			READ_ONCE(net->ipv4.sysctl_tcp_syn_retries);

		break;

	case TCP_LINGER2: