{
 "finding_id": "DF-2914",
 "status": "reproduced",
 "reproduced": 1,
 "impact": "none",
 "confidence": "certain",
 "verdict": "Mechanically reproduced via the harness on the stock guest: dev_is_good() returns 1 for a cdev AFTER destroy_dev + the devfs worker ran (with a held reference so the read is safe) - the function tests si_ops != &dead_dev_ops (kern_conf.c:127-132) but no code path ever installs dead_dev_ops (rg: definition + comments only; devfs_destroy_dev_worker never revectors), so every dead-device fence in the kernel (vfs_subr.c:1215/2531, vfs_conf.c:452/522, devfs_rules.c:298) is dead code and the kern_conf.c:336/:474 comments promise revectoring that never happens. No direct exploit: sysref keeps the cdev alive and dispatch reaches still-mapped driver ops (module-lifetime hazard is the DF-2896 family). On the fix kernel (SI_DESTROYED flag set in devfs_destroy_dev_worker, tested by dev_is_good) the same sequence returns 0.",
 "exploit_chain": "",
 "evidence": "harness.log T4: after-destroy=1; fix kernel T4: after-destroy=0",
 "kernel_refs": [
  "sys/kern/kern_conf.c:127",
  "sys/kfs/../kern/kern_conf.c:336",
  "sys/vfs/devfs/devfs_core.c:1440",
  "sys/kern/vfs_subr.c:1215"
 ],
 "poc_changes": "harness holds a cdev reference across destroy_dev and waits 2s for the async devfs worker",
 "attempts": 2,
 "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
 "runtime_sec": 60,
 "guest_dirty": 0,
 "build_cmd": "cd /root/h41 && make",
 "run_cmd": "kldload ./h41.ko; sysctl -w debug.h41.cmd=4",
 "code_hash": "85d6e241caa2a7fb1fb44b80c7736a4e83c36d29314b0c96ce91769bc9bdf839",
 "notes": "First harness attempt raced the async destroy worker (read before the flag existed)",
 "recommended_fix": "Set an SI_DESTROYED flag in devfs_destroy_dev_worker and test it in dev_is_good",
 "fix_status": "fixed",
 "fix_baseline_reproduced": 1,
 "fix_patched_reproduced": 0,
 "fix_kernel_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #1: Mon Oct 26 01:57:23 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64 (h41 fix kernel, all 41 hardening fixes applied)",
 "fix_verdict": "A/B: baseline after-destroy=1 (fence dead); fix kernel after-destroy=0 via SI_DESTROYED."
}