Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c
index 1a81e6a..c9544a4 100644
--- a/samples/bpf/tracex2_user.c
+++ b/samples/bpf/tracex2_user.c
@@ -131,7 +131,7 @@
 	signal(SIGTERM, int_exit);
 
 	/* start 'ping' in the background to have some kfree_skb events */
-	f = popen("ping -c5 localhost", "r");
+	f = popen("ping -4 -c5 localhost", "r");
 	(void) f;
 
 	/* start 'dd' in the background to have plenty of 'write' syscalls */