# DF-1272 PoC — tonga sclk_table->count Sclk_voltageOffset overflow

## Status
INCONCLUSIVE on the audit guest: **bug confirmed real by source trace at
sys/dev/drm/amd/powerplay/smumgr/tonga_smumgr.c:1620, but hardware-gated and not triggerable here.** fix.diff authored and
validated to apply + compile (nativekernel `rc=0`, `-Werror`). See
`VERDICT.md` for the full trace and `fix.diff` for the patch.

## Build
```sh
./build.sh
```
(equivalent: `cc -O2 -Wall -o tonga_sclk_voltage_offset_overflow tonga_sclk_voltage_offset_overflow.c`)

## Run (as unprivileged user)
```sh
./run.sh
```

## Expected on the audit guest
The PoC runs and reports that the kernel trigger surface is absent on this
QEMU/KVM guest (no LSI MegaRAID controller / no AMD Tonga GPU / no DP MST
hardware; mfi is in-kernel but `/dev/mfi0` is never created; drm/amdgpu are
loadable modules that are not loaded and would not attach). It exits 0 without
exercising the sink. The bug is therefore a **latent, hardware-dependent
defect**, not a false positive.

## Files
- `tonga_sclk_voltage_offset_overflow.c` — trigger / documentation PoC
- `fix.diff` — standalone `git apply -p1` patch closing the cited path
- `VERDICT.md` — full source-level mechanism + reachability + fix analysis
- `build.log` / `run.log` — captured build/run output
- `fix_build.log` — nativekernel compile-validation excerpt (`rc=0`)
- `env.txt` — guest environment
- `manifest.json` — machine-readable artifact catalog