diff --git a/extensions/xt_psd.c b/extensions/xt_psd.c
index 6cbe186..3bb7e33 100644
--- a/extensions/xt_psd.c
+++ b/extensions/xt_psd.c
@@ -26,6 +26,7 @@
 #include <linux/types.h>
 #include <linux/tcp.h>
 #include <linux/spinlock.h>
+#include <linux/vmalloc.h>
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_ipv6/ip6_tables.h>
 #include <net/ip.h>