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ipv6: annotate data races around np->min_hopcount

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

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2021-10-25 09:48:21 -07:00 committed by Jakub Kicinski
parent 09b8984667
commit cc17c3c8e8
2 changed files with 8 additions and 3 deletions
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5
net/ipv6/ipv6_sockglue.c
View File

@ -950,7 +950,10 @@ done:
goto e_inval;
if (val < 0 || val > 255)
goto e_inval;
np->min_hopcount = val;
/* tcp_v6_err() and tcp_v6_rcv() might read min_hopcount
* while we are changing it.
*/
WRITE_ONCE(np->min_hopcount, val);
retv = 0;
break;
case IPV6_DONTFRAG:

6
net/ipv6/tcp_ipv6.c
View File

@ -414,7 +414,8 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
if (sk->sk_state == TCP_CLOSE)
goto out;
if (ipv6_hdr(skb)->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {
/* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */
if (ipv6_hdr(skb)->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) {
__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
goto out;
}
@ -1726,7 +1727,8 @@ process:
return 0;
}
}
if (hdr->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {
/* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */
if (hdr->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) {
__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
goto discard_and_relse;
}