Input: refuse to register absolute devices without absinfo

If device is supposed to send absolute events (i.e. EV_ABS bit is set in
dev->evbit) but dev->absinfo is not allocated, then the driver has done
something wrong, and we should not register such device. Otherwise we'll
crash later, when driver tries to send absolute event.

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/input.c

@@ -2091,6 +2091,12 @@ int input_register_device(struct input_dev *dev)
 	const char *path;
 	int error;
 
+	if (test_bit(EV_ABS, dev->evbit) && !dev->absinfo) {
+		dev_err(&dev->dev,
+			"Absolute device without dev->absinfo, refusing to register\n");
+		return -EINVAL;
+	}
+
 	if (dev->devres_managed) {
 		devres = devres_alloc(devm_input_device_unregister,
 				      sizeof(struct input_devres), GFP_KERNEL);