diff --git a/sys/dev/usb/ehci.c b/sys/dev/usb/ehci.c
index bd4143298ff..661642f080c 100644
--- a/sys/dev/usb/ehci.c
+++ b/sys/dev/usb/ehci.c
@@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/endian.h>
 #include <sys/module.h>
 #include <sys/bus.h>
+#include <sys/lock.h>
 #include <sys/lockmgr.h>
 #if defined(DIAGNOSTIC) && defined(__i386__) && defined(__FreeBSD__)
 #include <machine/cpu.h>