diff --git a/sys/dev/snp/snp.c b/sys/dev/snp/snp.c
index d9f98975e15..3c20d3511cf 100644
--- a/sys/dev/snp/snp.c
+++ b/sys/dev/snp/snp.c
@@ -416,7 +416,7 @@ snpioctl(dev, cmd, data, flags, p)
 
 	switch (cmd) {
 	case SNPSTTY:
-		tdev = *((dev_t *) data);
+		tdev = udev2dev(*((udev_t *) data), 0);
 		if (tdev == NODEV)
 			return (snpdown(snp));
 
diff --git a/sys/kern/tty_snoop.c b/sys/kern/tty_snoop.c
index d9f98975e15..3c20d3511cf 100644
--- a/sys/kern/tty_snoop.c
+++ b/sys/kern/tty_snoop.c
@@ -416,7 +416,7 @@ snpioctl(dev, cmd, data, flags, p)
 
 	switch (cmd) {
 	case SNPSTTY:
-		tdev = *((dev_t *) data);
+		tdev = udev2dev(*((udev_t *) data), 0);
 		if (tdev == NODEV)
 			return (snpdown(snp));