diff --git a/drivers/isdn/mISDN/timerdev.c b/drivers/isdn/mISDN/timerdev.c
index 5b7e9bf..8785004 100644
--- a/drivers/isdn/mISDN/timerdev.c
+++ b/drivers/isdn/mISDN/timerdev.c
@@ -19,6 +19,7 @@
 
 #include <linux/poll.h>
 #include <linux/vmalloc.h>
+#include <linux/slab.h>
 #include <linux/timer.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>