=== DF-2587 PATCHED ng_ether.ko (NULL check in input/input_orphan/output) ===
kldload ng_ether (patched); kldload df2587_harness.ko (IFP2NG(vtnet0)=NULL)
ping -c2 10.0.2.2:
  64 bytes from 10.0.2.2: icmp_seq=0 ttl=255 time=0.136 ms
  64 bytes from 10.0.2.2: icmp_seq=1 ttl=255 time=0.284 ms
  2 packets transmitted, 2 received, 0.0% loss
PING_EXIT=0 ; guest stays UP (no panic)

=> fix_status: fixed. Same harness+ping; NULL check in ng_ether_output returns 0,
   packet passes through, no deref. Unpatched panicked at ng_ether_output+0x7.