--- a/extensions/pknock/xt_pknock.c
+++ b/extensions/pknock/xt_pknock.c
@@ -357,11 +357,18 @@
  *
  * @r: rule
  */
-static void
-peer_gc(unsigned long r)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+static void peer_gc(struct timer_list *tl)
+#else
+static void peer_gc(unsigned long r)
+#endif
 {
 	unsigned int i;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+	struct xt_pknock_rule *rule = from_timer(rule, tl, timer);
+#else
 	struct xt_pknock_rule *rule = (struct xt_pknock_rule *)r;
+#endif
 	struct peer *peer;
 	struct list_head *pos, *n;
 
@@ -469,9 +476,13 @@
 	if (rule->peer_head == NULL)
 		goto out;
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+	timer_setup(&rule->timer, peer_gc, 0);
+#else
 	init_timer(&rule->timer);
 	rule->timer.function	= peer_gc;
 	rule->timer.data	= (unsigned long)rule;
+#endif
 
 	rule->status_proc = proc_create_data(info->rule_name, 0, pde,
 	                    &pknock_proc_ops, rule);