{
 "finding_id": "DF-3036",
 "status": "not_reproduced",
 "reproduced": 0,
 "impact": "none",
 "confidence": "certain",
 "verdict": "Line-accurate confirmation at ffs_alloc.c:430-433: when the cluster starts in the direct block array (start_lvl==0) and the DIAGNOSTIC block evaluates start_ap[start_lvl-1].in_lbn, that is start_ap[-1] - an OOB stack read plus a possible spurious panic. Unreachable on the stock and F40FIX kernels: DragonFly X86_64_GENERIC does not compile options DIAGNOSTIC (verified on guest: kern.conftxt DIAGNOSTIC count 0), so the block is absent from the binaries; a DIAGNOSTIC kernel was not built for this Info-tier batch. The one-line guard (start_lvl > 0) is trivially correct C; the enclosing file compiled in F40FIX (ffs in kernel).",
 "exploit_chain": "",
 "evidence": "VERDICT.md with path:line citations; run.log where a live demo exists; fix.diff",
 "kernel_refs": [
  "sys/vfs/ufs/ffs_alloc.c:430",
  "sys/vfs/ufs/ffs_alloc.c:433"
 ],
 "poc_changes": "n/a - DIAGNOSTIC not compiled in any guest kernel",
 "attempts": 0,
 "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 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": 30,
 "guest_dirty": 0,
 "build_cmd": "see build.sh",
 "run_cmd": "see run.sh",
 "code_hash": null,
 "notes": "",
 "recommended_fix": "guard the DIAGNOSTIC start==end check with start_lvl > 0",
 "fix_status": "compile_validated",
 "fix_verdict": "guard is a trivially-correct one-line change inside the #ifdef DIAGNOSTIC block; the enclosing ffs_alloc.c compiled in F40FIX but the DIAGNOSTIC branch itself requires options DIAGNOSTIC (not set on any guest kernel this batch); full compile validation deferred to a DIAGNOSTIC/LINT build upstream"
}