Error Handling

Rust’s error handling model — Result, ?, and typed errors — is central to writing reliable kernel code.

Propagate errors with ? (propagate-errors)

Use the ? operator to propagate errors idiomatically. In kernel code, .unwrap() is rejected wherever failure is a legitimate possibility.

// Good — propagate with ?
let tsc_info = cpuid.get_tsc_info()?;
let frequency = tsc_info.nominal_frequency()?;

// Bad — unwrap hides the failure path
let tsc_info = cpuid.get_tsc_info().unwrap();

See also: The Rust Programming Language, Chapter 9 “Error Handling” and Rust by Example: unpacking options and defaults with ?.