diff --git a/net/core/sock.c b/net/core/sock.c
index 666a17cab4f56..b0dd501dabd6a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -765,7 +765,8 @@ 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_test_bit(MC_LOOP, sk);
 #if IS_ENABLED(CONFIG_IPV6)