{
  "finding_id": "DF-3906",
  "title": "xl_stop()/xl_stats_update() AB-BA callout deadlock (DF-3715 family, 10th instance, non-MPSAFE callout)",
  "file": "sys/dev/netif/xl/if_xl.c",
  "impact": "permanent-kernel-wedge DoS on 3c90x hardware; mechanism proven on guest via protocol replica",
  "verdict": "inconclusive (mechanism PROVEN via replica, hardware-gated)",
  "reproduce": {
    "build": "cd /root/kmod && make (KMOD=xl_callout_replica SRCS=xl_callout_replica.c)",
    "run": "kldload /root/kmod/xl_callout_replica.ko; sysctl kern.xlreplica_arm=1; sleep 1; (sysctl kern.xlreplica_stop=1 >/dev/null 2>&1 &)",
    "expected": "serial console: 'xlreplica[stop]: tick INPROG and PARKED on the serializer (fired=2 ran=1)' + terminal marker; stopper D/costp; softclock B/slize; callout_stop never returns; shutdown wedges"
  },
  "kernel_refs": [
    "sys/dev/netif/xl/if_xl.c:1320",
    "sys/dev/netif/xl/if_xl.c:2377",
    "sys/dev/netif/xl/if_xl.c:2429",
    "sys/dev/netif/xl/if_xl.c:3169",
    "sys/kern/kern_timeout.c:920"
  ],
  "artifacts": [
    "README.md",
    "VERDICT.md",
    "xl_callout_replica.c",
    "xl_callout_replica_fixed.c",
    "build.sh",
    "run.sh",
    "run.log",
    "console_markers.txt",
    "fix_validation.log",
    "env.txt",
    "fix.diff",
    "manifest.json",
    "verdict.json"
  ]
}