diff --git a/sys/dev/ichsmb/ichsmb_pci.c b/sys/dev/ichsmb/ichsmb_pci.c
index 8dfa6df5412..24c4423e8a1 100644
--- a/sys/dev/ichsmb/ichsmb_pci.c
+++ b/sys/dev/ichsmb/ichsmb_pci.c
@@ -48,6 +48,7 @@
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/errno.h>
+#include <sys/mutex.h>
 #include <sys/syslog.h>
 #include <sys/bus.h>