diff --git a/sys/dev/usb/usbdi.c b/sys/dev/usb/usbdi.c
index e26d8c3bf75..78c459f2a45 100644
--- a/sys/dev/usb/usbdi.c
+++ b/sys/dev/usb/usbdi.c
@@ -56,6 +56,7 @@
 #endif
 #endif
 #include <sys/malloc.h>
+#include <sys/proc.h>
 
 #include <machine/bus.h>