$ touch a
$ cksum -a md5 a > a.md5
$ run0 dmsetup create ioerr --table "0 8 error"
$ run0 chmod 777 /dev/mapper/ioerr
$ ln -sf /dev/mapper/ioerr a
$ cksum --check a.md5

thread 'main' (2345) panicked at src/uucore/src/lib/features/checksum/validate.rs:680:74:
called `Result::unwrap()` on an `Err` value: Os { code: 5, kind: Uncategorized, message: "Input/output error" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace