pretty_size_mode(devinfo->device_size, unit_mode));
printf(" Device slack: %*s%10s\n",
(int)(20 - strlen("Device slack")), "",
- pretty_size_mode(devinfo->device_size - devinfo->size,
+ pretty_size_mode(devinfo->device_size > 0 ?
+ devinfo->device_size - devinfo->size : 0,
unit_mode));
}