D387 - A diagnostic instrument only covers memory a run has published

Status: decided Date: 2026-08-30

A guest thread publishes its own stack span, into a fixed, lock-free registry, the moment the thread exists; every instrument that reads guest memory checks a request against the ranges a run has published and reports what it cannot see as unknown rather than as a wild pointer.

Why: The set of readable ranges is fixed once before a guest starts, but a guest thread's stack does not exist at that moment, so every instrument reading one reported a false "wild pointer" verdict about its own blind spot. Publishing a thread's span as soon as it has one, without allocating or locking, keeps that registry usable from the same restricted context the dispatch path runs in (D381).

Rejected:

• Publishing every readable range once at guest entry: correct for the image and the main stack, silent about every thread stack created afterward.