From: Runyu Xiao <runyu.xiao@seu.edu.cn>
Date: Tue, 2 Jun 2026 00:25:06 +0000 (+0800)
Subject: ipv6: use READ_ONCE() in ipv6_flowlabel_get()
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=f425c55cb60e116a53f2c196100dc09c5a828383;p=thirdparty%2Flinux.git

ipv6: use READ_ONCE() in ipv6_flowlabel_get()

ipv6_flowlabel_get() reads flowlabel_consistency and
flowlabel_state_ranges locklessly.

Use READ_ONCE() for these sysctl accesses.

Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260602002506.1519901-1-runyu.xiao@seu.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index b1ccdf0dc646..1ab5ad0dcf24 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -620,7 +620,7 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 	int err;
 
 	if (freq->flr_flags & IPV6_FL_F_REFLECT) {
-		if (net->ipv6.sysctl.flowlabel_consistency) {
+		if (READ_ONCE(net->ipv6.sysctl.flowlabel_consistency)) {
 			net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 			return -EPERM;
 		}
@@ -633,7 +633,7 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 
 	if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
 		return -EINVAL;
-	if (net->ipv6.sysctl.flowlabel_state_ranges &&
+	if (READ_ONCE(net->ipv6.sysctl.flowlabel_state_ranges) &&
 	    (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
 		return -ERANGE;