D471 - The fault reporter verifies a page is readable before reading it

Status: decided Date: 2026-09-02

Before copying the machine code around a fault address into a report, the reporter checks that the memory is committed and readable, rather than assuming the faulting instruction pointer always names mapped memory.

Why: on an execute fault the instruction pointer itself is the unmapped address, so reading through it faults a second time inside the fault handler, which ends the process and leaves no report at all.

Rejected:

• Assuming the faulting address is always readable because it belongs to "the instruction that just faulted": true of a data fault, false of an execute fault, and the failure mode is a silently unreported run rather than a wrong one.