diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index fa534fe4864b33..38e4fcb418c0f5 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1633,6 +1633,11 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 	/* Device config is special, because it must work on
 	 * an unconfigured device. */
 	if (cmd == COMEDI_DEVCONFIG) {
+		if (minor >= COMEDI_NUM_BOARD_MINORS) {
+			/* Device config not appropriate on non-board minors. */
+			rc = -ENOTTY;
+			goto done;
+		}
 		rc = do_devconfig_ioctl(dev,
 					(struct comedi_devconfig __user *)arg);
 		if (rc == 0)