diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 701452a..ed01f3b 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
+#include <linux/slab.h>
 #include <linux/tty_flip.h>
 #include <linux/serial.h>
 #include <linux/module.h>