{
  "finding_id": "DF-3903",
  "title": "sk_stop()/sk_tick()/sk_yukon_tick() AB-BA callout deadlock (DF-3715 family, 7th instance, non-MPSAFE callout)",
  "file": "sys/dev/netif/sk/if_sk.c",
  "impact": "permanent-kernel-wedge DoS on sk hardware (both ports of dual-port cards); mechanism proven on guest via protocol replica",
  "verdict": "inconclusive (mechanism PROVEN via replica, hardware-gated)",
  "reproduce": {
    "build": "cd /root/kmod && make (KMOD=sk_callout_replica SRCS=sk_callout_replica.c)",
    "run": "kldload /root/kmod/sk_callout_replica.ko; sysctl kern.skreplica_arm=1; sleep 1; (sysctl kern.skreplica_stop=1 >/dev/null 2>&1 &)",
    "expected": "serial console: 'skreplica[stop]: tick INPROG and PARKED on the serializer (fired=2 ran=1)' + terminal marker; stopper D0/costp; softclock B/slize; callout_stop never returns; shutdown wedges"
  },
  "kernel_refs": [
    "sys/dev/netif/sk/if_sk.c:1311",
    "sys/dev/netif/sk/if_sk.c:2041",
    "sys/dev/netif/sk/if_sk.c:2067",
    "sys/dev/netif/sk/if_sk.c:2087",
    "sys/dev/netif/sk/if_sk.c:2089",
    "sys/dev/netif/sk/if_sk.c:2778",
    "sys/dev/netif/sk/if_sk.c:2782",
    "sys/kern/kern_timeout.c:920"
  ],
  "artifacts": [
    "README.md",
    "VERDICT.md",
    "sk_callout_replica.c",
    "sk_callout_replica_fixed.c",
    "build.sh",
    "run.sh",
    "build_shared.log",
    "run.log",
    "console_markers.txt",
    "fix_validation.log",
    "env.txt",
    "fix.diff",
    "manifest.json",
    "verdict.json"
  ]
}