[PATCH 6.19 284/844] ipv6: annotate data-races over sysctl.flowlabel_reflect

[Sasha Levin]

From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 5ade47c974b46eb2a1279185962a0ffa15dc5450 ]

Add missing READ_ONCE() when reading ipv6.sysctl.flowlabel_reflect,
as its value can be changed under us.

Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
Link: https://patch.msgid.link/20260115094141.3124990-6-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/ipv6/af_inet6.c | 4 ++--
 net/ipv6/icmp.c     | 3 ++-
 net/ipv6/tcp_ipv6.c | 3 ++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index d3534bdb805da..56d453a598ec6 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -224,8 +224,8 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol,
 	inet6_set_bit(MC6_LOOP, sk);
 	inet6_set_bit(MC6_ALL, sk);
 	np->pmtudisc	= IPV6_PMTUDISC_WANT;
-	inet6_assign_bit(REPFLOW, sk, net->ipv6.sysctl.flowlabel_reflect &
-				     FLOWLABEL_REFLECT_ESTABLISHED);
+	inet6_assign_bit(REPFLOW, sk, READ_ONCE(net->ipv6.sysctl.flowlabel_reflect) &
+				      FLOWLABEL_REFLECT_ESTABLISHED);
 	sk->sk_ipv6only	= net->ipv6.sysctl.bindv6only;
 	sk->sk_txrehash = READ_ONCE(net->core.sysctl_txrehash);
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 55b1aa75ab802..0f41ca6f3d83e 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -953,7 +953,8 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb)
 	tmp_hdr.icmp6_type = type;
 
 	memset(&fl6, 0, sizeof(fl6));
-	if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
+	if (READ_ONCE(net->ipv6.sysctl.flowlabel_reflect) &
+	    FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
 		fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb));
 
 	fl6.flowi6_proto = IPPROTO_ICMPV6;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 280fe59785598..4ae664b05fa91 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1085,7 +1085,8 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb,
 			txhash = inet_twsk(sk)->tw_txhash;
 		}
 	} else {
-		if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET)
+		if (READ_ONCE(net->ipv6.sysctl.flowlabel_reflect) &
+		    FLOWLABEL_REFLECT_TCP_RESET)
 			label = ip6_flowlabel(ipv6h);
 	}
 
-- 
2.51.0