{
  "finding_id": "DF-4310",
  "title": "ste_stop/ste_intr STATS_OFLOW: synchronous callout_stop under if_serializer vs ste_stats_update blocking-enter — AB-BA deadlock (DF-3715 family)",
  "verdict": "mechanism_proven_replica",
  "impact": "dos",
  "driver_runtime": "hardware_gated_no_st201_in_qemu",
  "reproduce": {
    "build": "cd /root/kmod && make   (ste_callout_replica.c + Makefile on guest)",
    "run": "kldload ste_callout_replica.ko; sysctl kern.sterplica.arm=1; sysctl kern.sterplica.stop_fixed=1; (sysctl kern.sterplica.stop_blk=1 &); sleep 10; dmesg | grep sterplica; ps -o pid,stat,wchan,command -ax | grep stop_blk",
    "expected": "stop_fixed returns (pending=0); stop_blk never returns; ps shows D4 wchan=costp; guest can no longer shut down cleanly (MP lock held by parked tick)"
  },
  "kernel_refs": [
    "sys/dev/netif/ste/if_ste.c:914",
    "sys/dev/netif/ste/if_ste.c:1220",
    "sys/dev/netif/ste/if_ste.c:790",
    "sys/dev/netif/ste/if_ste.c:811",
    "sys/dev/netif/ste/if_ste.c:1231",
    "sys/dev/netif/ste/if_ste.c:607",
    "sys/dev/netif/ste/if_ste.c:997",
    "sys/dev/netif/ste/if_ste.c:1130",
    "sys/dev/netif/ste/if_ste.c:1494",
    "sys/dev/netif/ste/if_ste.c:1507",
    "sys/dev/netif/ste/if_ste.c:974",
    "sys/kern/kern_timeout.c:1091",
    "sys/kern/kern_timeout.c:859",
    "sys/kern/kern_timeout.c:920",
    "sys/kern/kern_timeout.c:580",
    "sys/net/if.c:1900"
  ],
  "artifacts": [
    "ste_callout_replica.c", "Makefile", "build.sh", "build.log",
    "run.sh", "run.log", "env.txt", "VERDICT.md", "README.md",
    "fix.diff", "manifest.json", "verdict.json"
  ]
}