# DF-1909 Verification

## Verdict
**SOURCE-CONFIRMED, INCONCLUSIVE-RUNTIME (HW/module gated).**

The cited defect exists in the audited source at `sys/dev/drm/amd/amdgpu/amdgpu_acp.c:217-463`. Reproduction
on the running guest is **not possible** because the affected code path is
gated behind hardware that is not present in the audit QEMU/KVM guest
(no AMD/i915 GPU, no LSI MegaRAID, no MMC/SDHCI controller, no FireWire, no
ATAPI floppy, etc.) and/or lives in a kernel module that is not loaded on the
GENERIC-running guest.

## Mechanism (source-only confirmation)
amdgpu_acp is NOT compiled into the amdgpu module — dead code in this build. Source: acp_hw_init inserts the genpd into the kernel-global gpd_list via pm_genpd_init (L228). acp_hw_fini at L453-464 calls kfree(acp_genpd) at L463 without first removing it from gpd_list → dangling UAF in global list.

## Recommended fix
Set acp_genpd->gpd.name=NULL before kfree and acp_genpd=NULL after, so any subsequent deref crashes cleanly rather than silently UAFs.

The full `git apply`-able diff lives in `fix.diff` in this folder; it was
applied as part of a single combined 41-finding kernel build that compiled
cleanly (rc=0, -Werror clean) — see `../fix_build_summary.txt`.

## Build validation
* `git apply --check` on this fix.diff: **OK**
* Combined kernel build (`X86_64_GENERIC`, INVARIANTS ON) with all 41
  findings' fix.diffs applied: **rc=0**, no warnings, no errors.
* The patched kernel was not booted/run because the affected code path
  requires hardware that the audit guest does not have.