diff --git a/drivers/isdn/mISDN/timerdev.c b/drivers/isdn/mISDN/timerdev.c
index 62b5e49684e5..f2b32186d4a1 100644
--- a/drivers/isdn/mISDN/timerdev.c
+++ b/drivers/isdn/mISDN/timerdev.c
@@ -86,7 +86,7 @@ mISDN_close(struct inode *ino, struct file *filep)
 }
 
 static ssize_t
-mISDN_read(struct file *filep, char *buf, size_t count, loff_t *off)
+mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off)
 {
 	struct mISDNtimerdev	*dev = filep->private_data;
 	struct mISDNtimer	*timer;
@@ -116,7 +116,7 @@ mISDN_read(struct file *filep, char *buf, size_t count, loff_t *off)
 		timer = (struct mISDNtimer *)dev->expired.next;
 		list_del(&timer->list);
 		spin_unlock_irqrestore(&dev->lock, flags);
-		if (put_user(timer->id, (int *)buf))
+		if (put_user(timer->id, (int __user *)buf))
 			ret = -EFAULT;
 		else
 			ret = sizeof(int);