diff --git a/net/core/sock.c b/net/core/sock.c
index 4e3ed80a68ce..385ce723fc29 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -632,7 +632,8 @@ bool sk_mc_loop(struct sock *sk)
 		return false;
 	if (!sk)
 		return true;
-	switch (sk->sk_family) {
+	/* IPV6_ADDRFORM can change sk->sk_family under us. */
+	switch (READ_ONCE(sk->sk_family)) {
 	case AF_INET:
 		return inet_sk(sk)->mc_loop;
 #if IS_ENABLED(CONFIG_IPV6)