Commit 14834c4f authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

ipv4: annotate data races arount inet->min_ttl 



No report yet from KCSAN, yet worth documenting the races.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 790eb673

net/ipv4/ip_sockglue.c

+4 −1
Original line number Diff line number Diff line
@@ -1352,7 +1352,10 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname, 
			goto e_inval;

		if (val < 0 || val > 255)

			goto e_inval;

		inet->min_ttl = val;

		/* tcp_v4_err() and tcp_v4_rcv() might read min_ttl

		 * while we are changint it.

		 */

		WRITE_ONCE(inet->min_ttl, val);

		break;



	default:

net/ipv4/tcp_ipv4.c

+5 −2
Original line number Diff line number Diff line
@@ -508,7 +508,8 @@ int tcp_v4_err(struct sk_buff *skb, u32 info) 
	if (sk->sk_state == TCP_CLOSE)

		goto out;



	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {

	/* min_ttl can be changed concurrently from do_ip_setsockopt() */

	if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {

		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);

		goto out;

	}
@@ -2068,7 +2069,9 @@ int tcp_v4_rcv(struct sk_buff *skb) 
			return 0;

		}

	}

	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {



	/* min_ttl can be changed concurrently from do_ip_setsockopt() */

	if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {

		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);

		goto discard_and_relse;

	}