diff --git a/net/core/sock.c b/net/core/sock.c
index fa60b7494c58..d5e302e21e85 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3911,7 +3911,14 @@ int sock_gettstamp(struct socket *sock, void __user *userstamp,
 	struct sock *sk = sock->sk;
 	struct timespec64 ts;
 
-	sock_enable_timestamp(sk, SOCK_TIMESTAMP);
+	/* sk->sk_flags must only be changed under the socket lock,
+	 * because sock_set_flag() uses non atomic operations.
+	 */
+	if (!sock_flag(sk, SOCK_TIMESTAMP)) {
+		lock_sock(sk);
+		sock_enable_timestamp(sk, SOCK_TIMESTAMP);
+		release_sock(sk);
+	}
 	ts = ktime_to_timespec64(sock_read_timestamp(sk));
 	if (ts.tv_sec == -1)
 		return -ENOENT;