Guest: DragonFly dfbsd 6.5-DEVELOPMENT x86_64, QEMU/KVM (qemu-system-x86_64 -enable-kvm -m 4096 -smp 6)
Baseline kernel #0: Thu Jul  2 06:02:54 UTC 2026 (stock X86_64_GENERIC, `device et` built in)
Fixed kernel   #1: Wed Oct 14 21:12:27 UTC 2026 (same tree + fix.diff; /usr/src/sys/dev/netif/et/if_et.c patched, make -j6 nativekernel + installkernel, 37,669-line build log, BUILD_OK)
Compiler: cc 8.3 [DragonFly] Release/2019-02-22
No ET131x (Agere/LSI ET-1010) NIC on the guest; et(4) is built-in (statics resolved from /boot/kernel/kernel via nm(1)):
  baseline: et_intr=ffffffff804b8bd0 (contains inlined et_rxeof) et_txeof=ffffffff804b6740 et_stop=ffffffff804b5ed0
            et_tick=ffffffff804b87d0 et_newbuf_hdr=ffffffff804b9450 et_newbuf_cluster=ffffffff804b9460
  fixed:    et_intr=ffffffff804b8c70 et_txeof=ffffffff804b6740 et_stop=ffffffff804b5ed0
            et_tick=ffffffff804b8820 et_newbuf_hdr=ffffffff804b9560 et_newbuf_cluster=ffffffff804b9570
Struct layout cross-check (module vs kernel): sizeof(et_softc)=0x85c8 sc_tick=+0x400 sc_rx_data=+0x520
  sc_tx_data=+0x6568 sc_rxstat_ring=+0x480 sc_rx_status=+0x4a8 if_timer=+0x6a MHLEN=248 MCLBYTES=2048
  ET_RX_NSTAT=1024 ET_TX_NDESC=512
/usr/src md5(if_et.c) = 70a222f46468a5d29d0772af7b85a392 (identical to audit tree sys/dev/netif/et/if_et.c)