Commit 5ecf9d4f authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: annotate data-races around tp->keepalive_intvl 



do_tcp_getsockopt() reads tp->keepalive_intvl 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/20230719212857.3943972-5-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 4164245c

include/net/tcp.h

+7 −2
Original line number Diff line number Diff line
@@ -1509,9 +1509,14 @@ void tcp_leave_memory_pressure(struct sock *sk); 
static inline int keepalive_intvl_when(const struct tcp_sock *tp)

{

	struct net *net = sock_net((struct sock *)tp);

	int val;



	/* Paired with WRITE_ONCE() in tcp_sock_set_keepintvl()

	 * and do_tcp_setsockopt().

	 */

	val = READ_ONCE(tp->keepalive_intvl);



	return tp->keepalive_intvl ? :

		READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl);

	return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl);

}



static inline int keepalive_time_when(const struct tcp_sock *tp)

net/ipv4/tcp.c

+2 −2
Original line number Diff line number Diff line
@@ -3345,7 +3345,7 @@ int tcp_sock_set_keepintvl(struct sock *sk, int val) 
		return -EINVAL;



	lock_sock(sk);

	tcp_sk(sk)->keepalive_intvl = val * HZ;

	WRITE_ONCE(tcp_sk(sk)->keepalive_intvl, val * HZ);

	release_sock(sk);

	return 0;

}
@@ -3559,7 +3559,7 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname, 
		if (val < 1 || val > MAX_TCP_KEEPINTVL)

			err = -EINVAL;

		else

			tp->keepalive_intvl = val * HZ;

			WRITE_ONCE(tp->keepalive_intvl, val * HZ);

		break;

	case TCP_KEEPCNT:

		if (val < 1 || val > MAX_TCP_KEEPCNT)