media: cpia2: fix memory leak in cpia2_usb_probe

syzbot reported leak in cpia2 usb driver. The problem was
in invalid error handling.

v4l2_device_register() is called in cpia2_init_camera_struct(), but
all error cases after cpia2_init_camera_struct() did not call the
v4l2_device_unregister()

Reported-by: [e-mail]
Signed-off-by: Pavel Skripkin <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/usb/cpia2/cpia2.h

···
 int cpia2_do_command(struct camera_data *cam,
 		     unsigned int command,
 		     unsigned char direction, unsigned char param);
+void cpia2_deinit_camera_struct(struct camera_data *cam, struct usb_interface *intf);
 struct camera_data *cpia2_init_camera_struct(struct usb_interface *intf);
 int cpia2_init_camera(struct camera_data *cam);
 int cpia2_allocate_buffers(struct camera_data *cam);

drivers/media/usb/cpia2/cpia2_core.c

···
  *
  *  cpia2_init_camera_struct
  *
+ *  Deinitialize camera struct
+ *****************************************************************************/
+void cpia2_deinit_camera_struct(struct camera_data *cam, struct usb_interface *intf)
+{
+	v4l2_device_unregister(&cam->v4l2_dev);
+	kfree(cam);
+}
+
+/******************************************************************************
+ *
+ *  cpia2_init_camera_struct
+ *
  *  Initializes camera struct, does not call reset to fill in defaults.
  *****************************************************************************/
 struct camera_data *cpia2_init_camera_struct(struct usb_interface *intf)

drivers/media/usb/cpia2/cpia2_usb.c

···
 	ret = set_alternate(cam, USBIF_CMDONLY);
 	if (ret < 0) {
 		ERR("%s: usb_set_interface error (ret = %d)\n", __func__, ret);
-		kfree(cam);
-		return ret;
+		goto alt_err;
 	}
 
 
 	if((ret = cpia2_init_camera(cam)) < 0) {
 		ERR("%s: failed to initialize cpia2 camera (ret = %d)\n", __func__, ret);
-		kfree(cam);
-		return ret;
+		goto alt_err;
 	}
 	LOG("  CPiA Version: %d.%02d (%d.%d)\n",
 	       cam->params.version.firmware_revision_hi,
···
 	ret = cpia2_register_camera(cam);
 	if (ret < 0) {
 		ERR("%s: Failed to register cpia2 camera (ret = %d)\n", __func__, ret);
-		kfree(cam);
-		return ret;
+		goto alt_err;
 	}
 
 	return 0;
+
+alt_err:
+	cpia2_deinit_camera_struct(cam, intf);
+	return ret;
 }
 
 /******************************************************************************