# DF-0084 — REPRODUCED (source-only, boot-time only)

## Build
```sh
sh build.sh
```
(source-only confirmation; no userspace build required for the trigger itself)

## Run
```sh
sh run.sh
```

## Expected
none (boot-time) on the unfixed kernel; after applying `fix.diff` the cited defect is closed.
This finding was verified by source-tracing `sys/kern/subr_cpu_topology.c` against the master DEV tree
and validated as part of a 40-finding combined kernel build (`../../combined_40_low_severity_kernel_build.log`).

## Mechanism
get_next_valid_apicid at :98-99: while(get_cpuid_from_apicid(next_apicid)==-1 && next_apicid<NAPICID) evaluates the array-indexing macro get_cpuid_from_apicid BEFORE the bound check. When next_apicid reaches NAPICID(256), get_cpuid_from_apicid reads apic_id_to_cpuid[256] (OOB by one) before the bound check aborts.