D447 - A system knob is answered only from a source this project can cite

Status: decided Date: 2026-09-01

sysctlbyname answers a fixed set of named knobs it has a citable value for, and refuses every other name.

Why: A refused system knob is what turns off a guest's own workaround for it; answering an invented value instead would be read by a guest as a real fact about the platform. The target kernel's own family name is a citable constant; a configured release string comes from the active machine profile; nothing else here has a source.

Rejected: inventing a plausible value for an unmeasured knob so a guest's query succeeds - exactly the fabricated fact this project's honesty rule forbids.