diff -drupN a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
--- a/net/l2tp/l2tp_ip6.c	2018-08-06 17:23:04.000000000 +0300
+++ b/net/l2tp/l2tp_ip6.c	2022-06-12 05:28:14.000000000 +0300
@@ -526,6 +526,7 @@ static int l2tp_ip6_sendmsg(struct sock
 	memset(&fl6, 0, sizeof(fl6));
 
 	fl6.flowi6_mark = sk->sk_mark;
+	fl6.flowi6_uid = sk->sk_uid;
 
 	ipc6.hlimit = -1;
 	ipc6.tclass = -1;