{
  "finding_id": "DF-4355",
  "file": "sys/dev/netif/sn/if_sn.c",
  "title": "Unbounded MMUCR_BUSY busy-waits (4 sites) + device-fault no-exit loops: unrecoverable system hang on SMC91xx glitch or PCMCIA ejection",
  "verdict": { "status": "untested", "impact": "none", "confidence": "certain", "reason": "hardware-gated (SMC91xx PCMCIA absent from guest); source-level certainty" },
  "reproduce": {
    "build": "N/A - hardware-gated; no executable PoC",
    "run": "N/A (on real hardware: bring sn0 up, transfer traffic, eject the PCMCIA card mid-transfer)",
    "expected": "Hard hang (infinite spin in hard interrupt context holding the ifnet serializer); only recoverable by power cycle"
  },
  "kernel_refs": [
    "sys/dev/netif/sn/if_sn.c:275",
    "sys/dev/netif/sn/if_sn.c:641",
    "sys/dev/netif/sn/if_sn.c:871",
    "sys/dev/netif/sn/if_sn.c:1056",
    "sys/dev/netif/sn/if_sn.c:446",
    "sys/dev/netif/sn/if_sn.c:1063",
    "sys/dev/netif/sn/if_sn.c:415",
    "sys/dev/netif/sn/if_snreg.h:238",
    "sys/dev/netif/sn/if_snreg.h:60"
  ],
  "artifacts": [
    "README.md",
    "VERDICT.md",
    "fix.diff",
    "env.txt",
    "verdict.json",
    "manifest.json"
  ]
}