diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 493775f..cf8e703 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -32,6 +32,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/init.h>
 #include <linux/rbtree.h>
+#include <linux/slab.h>
 #include <net/sock.h>
 #include <net/gen_stats.h>