[PATCH net-next 4/9] sit: annotate data-races around tunnel->fwmark
From: Eric Dumazet <edumazet@google.com>
Date: 2026-09-07 07:58:55
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
ipip6_tunnel_xmit() runs locklessly (dev->lltx == true) and reads tunnel->fwmark. In preparation for converting ipip6_fill_info() to run without RTNL, add READ_ONCE() and WRITE_ONCE() annotations around tunnel->fwmark. Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/ipv6/sit.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 9a2bbd76d3794849cd11c6530ba1303bf53fa388..e85fa80e80d1ad2c593b860685b9f5bac21e66d9 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c@@ -929,7 +929,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, if (!dst && !ipip6_tunnel_dst_find(skb, &dst, false)) goto tx_error; - flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark, + flowi4_init_output(&fl4, tunnel->parms.link, READ_ONCE(tunnel->fwmark), tos & INET_DSCP_MASK, RT_SCOPE_UNIVERSE, IPPROTO_IPV6, 0, dst, tiph->saddr, 0, 0, sock_net_uid(tunnel->net, NULL));
@@ -1153,7 +1153,7 @@ static void ipip6_tunnel_update(struct ip_tunnel *t, t->parms.iph.frag_off = p->iph.frag_off; if (t->parms.link != p->link || t->fwmark != fwmark) { t->parms.link = p->link; - t->fwmark = fwmark; + WRITE_ONCE(t->fwmark, fwmark); ipip6_tunnel_bind_dev(t->dev); } dst_cache_reset(&t->dst_cache);
@@ -1706,7 +1706,7 @@ static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev) nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) || nla_put_be16(skb, IFLA_IPTUN_FLAGS, ip_tunnel_flags_to_be16(parm->i_flags)) || - nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark)) + nla_put_u32(skb, IFLA_IPTUN_FWMARK, READ_ONCE(tunnel->fwmark))) goto nla_put_failure; #ifdef CONFIG_IPV6_SIT_6RD
--
2.55.0.979.g7e5102b832-goog