diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 950cb31..ca9d866 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -37,6 +37,7 @@
 #include <linux/errno.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
+#include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/bitops.h>
 #include <linux/usb.h>