⬢ DragonFlyBSD Kernel Audit
DF-4901 / manifest.json
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{
  "finding_id": "DF-4901",
  "file": "sys/dev/drm/amd/amdgpu/cz_ih.c",
  "title": "cz_ih (Carrizo/Stoney): unvalidated device-DMA'd IH wptr — DF-4843/DF-4854/DF-4887 4th twin: permanent interrupt-thread spin on misaligned wptr + RB_OVERFLOW +16 recovery importing the bad phase → up to 12-byte OOB read past the zero-slack 64 KiB GTT ring BO",
  "verdict": "untested",
  "impact": "dos",
  "severity": "Low",
  "confidence": "certain",
  "reproduce": {
    "build": "n/a — device-gated (wptr is GPU DMA into the writeback slot); guest has no AMD GPU (env.txt)",
    "run": "n/a",
    "expected": "if armed on CZ/Stoney hardware: amdgpu ithread pegs one CPU forever re-dispatching the 64KiB ring (all GPU IRQs dead); with overflow bit + wptr phase 4..15 near ring end: first decode reads up to 12B past the ring BO"
  },
  "kernel_refs": [
    "sys/dev/drm/amd/amdgpu/cz_ih.c:192",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:194",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:202",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:207",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:225",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:253",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:266",
    "sys/dev/drm/amd/amdgpu/cz_ih.c:300",
    "sys/dev/drm/amd/amdgpu/amdgpu_ih.c:80",
    "sys/dev/drm/amd/amdgpu/amdgpu_ih.c:154",
    "sys/dev/drm/amd/amdgpu/vi.c:1671"
  ],
  "artifacts": ["README.md", "VERDICT.md", "trigger_sketch.c", "twin_diff.cz-vs-tonga.txt", "fix.diff", "verdict.json", "manifest.json", "env.txt"]
}