{
  "finding_id": "DF-4489",
  "status": "untested",
  "reproduced": 0,
  "impact": "none",
  "confidence": "certain",
  "verdict": "Porting divergence in apply_below_the_range (freesync.c:250-252,357-360): min_frame_duration_in_ns is computed then never used, and the clamp compares inserted_frame_duration_in_us against (1000000 / max_refresh_in_uhz) which is 0 for every real refresh in uHz (correct arithmetic is 1e12/refresh_uHz, cf. upstream Linux amd display min_frame_duration_in_ns / 1000). The clamp is dead -> BTR may insert frames below the panel minimum refresh (flicker); no memory-safety impact (v_total is re-clamped to [min,max] duration and nominal v_total in calc_v_total_from_duration :146-160). AMD-GPU-gated: audit guest has no AMD device (virtio-gpu only), so not runtime-testable. Info severity.",
  "exploit_chain": "",
  "evidence": "VERDICT.md (arithmetic proof: 1000000/144000000 == 0)",
  "kernel_refs": [
    "sys/dev/drm/amd/display/modules/freesync/freesync.c:250",
    "sys/dev/drm/amd/display/modules/freesync/freesync.c:357"
  ],
  "poc_changes": "",
  "attempts": 0,
  "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
  "runtime_sec": 0,
  "guest_dirty": 0,
  "build_cmd": "",
  "run_cmd": "",
  "code_hash": "",
  "notes": "Guest pciconf shows no vendor 0x1002 device; amdgpu/DC freesync unreachable in QEMU.",
  "recommended_fix": "Use min_frame_duration_in_ns/1000 (i.e. div64_u64(1000000000000ULL, max_refresh_in_uhz)) for the inserted_frame_duration_in_us clamp",
  "fix_status": "not_testable",
  "fix_baseline_reproduced": 0,
  "fix_patched_reproduced": 0,
  "fix_verdict": "No AMD hardware on the audit guest; static arithmetic proof only.",
  "fix_evidence": ""
}