Guest environment for DF-3333 verification (2026-09-11).

uname -a:
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

kern.ident = X86_64_GENERIC, 6 CPUs, 4 GB RAM, virtio (vtnet0, lo0).

# netmap subsystem availability on this guest/tree  (same as DF-3332)
- /dev/netmap does not exist; kldload netmap -> "No such file or directory";
  cd /usr/src/sys/net/netmap && make -> 15 hard errors
  ('struct ifnet' has no member named 'if_unused7', netmap_kern.h:747);
  no sys/conf/files entry, no kernel config includes netmap.
  => verbatim-function KLD approach (df3333_kmod.c) used instead.

# PoC module builds (final successful): build.log
# Decisive runs (dmesg.txt, run.log, run.fixed.log):
1. vulnerable: 4194302 lie-pairs -> hwcur=2048 hwavail=0 -> transmit wrote
   slot[1024] (lim=1023): OOB WRITE CONFIRMED past end of slot array.
2. fixed (rxpos modulo): transmit used slot[0], no write past ring end.