From 7d4c7533b632cc500b64412522f4eaabedbc2eed Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 15 Jan 2026 09:41:38 +0000 Subject: [PATCH] ipv6: annotate data-races over sysctl.flowlabel_reflect [ 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 Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260115094141.3124990-6-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- 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 0e8f48835869..3709f213d33d 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -224,8 +224,8 @@ lookup_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 35b32dcf581f..54ad4c757867 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -757,7 +757,8 @@ 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 59c4977a811a..2e07dba293b4 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1131,7 +1131,8 @@ 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); }