{
  "finding_id": "DF-3815",
  "status": "inconclusive",
  "reproduced": 0,
  "impact": "none",
  "confidence": "certain",
  "verdict": "Arithmetic is source-certain: sges_per_frame = IOCMaxChainSegmentSize - 1 (mpr.c:416 via chain_frame_size = seg*16), only ==0 is guarded (mpr.c:399), and mpr.c:431-432 divides by sges_per_frame — a device reporting 1 in IOC Facts (trusted doorbell data) panics the kernel with a divide-by-zero trap at attach or reallocating reinit. Runtime inconclusive: driver compiled in but no SAS3 controller on the guest to supply crafted facts (probe.log).",
  "exploit_chain": "",
  "evidence": "VERDICT.md arithmetic proof; fix.diff (< 2 clamp).",
  "kernel_refs": ["sys/dev/raid/mpr/mpr.c:399", "sys/dev/raid/mpr/mpr.c:416", "sys/dev/raid/mpr/mpr.c:431-432"],
  "poc_changes": "No runnable PoC without a device; source-level only.",
  "attempts": 1,
  "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": 5,
  "guest_dirty": 0,
  "build_cmd": "",
  "run_cmd": "",
  "notes": "Device-trust class (same trust model as DF-1228 SMID, different sink). Upstream-shared with FreeBSD mpr.",
  "recommended_fix": "Clamp IOCMaxChainSegmentSize < 2 to MPR_DEFAULT_CHAIN_SEG_SIZE in mpr_resize_queues().",
  "fix_status": "not_testable",
  "fix_baseline_reproduced": 0,
  "fix_patched_reproduced": 0,
  "fix_verdict": "No SAS3 hardware on guest; baseline/patched kernels cannot be driven through IOC Facts parsing.",
  "fix_evidence": "fix.diff."
}