diff --git a/src/devices/pnp_device.c b/src/devices/pnp_device.c
index b2bca03232..a6d428abed 100644
--- a/src/devices/pnp_device.c
+++ b/src/devices/pnp_device.c
@@ -170,6 +170,12 @@ static void pnp_get_ioresource(device_t dev, u8 index, struct io_info *info)
 	struct resource *resource;
 	unsigned moving, gran, step;
 
+	if (!info->mask) {
+		printk(BIOS_ERR, "ERROR: device %s index %d has no mask.\n",
+				dev_path(dev), index);
+		return;
+	}
+
 	resource = new_resource(dev, index);
 
 	/* Initilize the resource. */