df1326_replica build log (vulnerable variant, no -DFIXED) — DragonFly 6.5-DEVELOPMENT guest
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026  root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64
Command: cd /root/df1326 && make SYSDIR=/usr/src/sys MACHINE=x86_64 MACHINE_ARCH=x86_64

Warning: Object directory not changed from original /root/df1326
dragonfly -> /usr/src/sys
machine_base -> /usr/src/sys/platform/pc64
machine -> /usr/src/sys/platform/pc64/include
cpu_base -> /usr/src/sys/cpu/x86_64
cpu -> /usr/src/sys/cpu/x86_64/include
[66x forwarding headers created: machine/*.h, sys/*.h]
cc  -O2 -pipe   -D_KERNEL -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Wcast-qual  -Wold-style-definition -Wmissing-include-dirs  -Wno-pointer-sign -Winit-self -Wundef -Wno-unused-but-set-variable -std=gnu11 -Werror -DKLD_MODULE -nostdinc  -I. -Idragonfly -I/root/df1326/forwarder_x86_64/include -Idragonfly/../include -I/usr/include  -Wold-style-declaration -fno-common -ffreestanding -fno-stack-protector -fno-strict-aliasing -fno-strict-overflow -fno-asynchronous-unwind-tables -fno-omit-frame-pointer -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float -mno-fp-ret-in-387 -mindirect-branch=thunk-inline   -c df1326_replica.c
cc -Wl,--build-id=sha1 -nostdlib -Wl,--hash-style=sysv   -r -Wl,-d -o df1326.ko df1326_replica.o
===> rc=0, df1326.ko produced (note: -fno-stack-protector in the kernel/module
      CFLAGS — the shipped kernel has no stack canary: `nm /boot/kernel/kernel
      | grep -c stack_chk` -> 0)

Fixed variant (Makefile.fixed, COPTS+=-DFIXED): identical cc line plus
"-DFIXED" before "-c df1326_replica.c", rc=0 (verified: grep -c -- -DFIXED
/tmp/build_fixed.log -> 1). NOTE: CFLAGS+=-DFIXED in the Makefile does NOT
work — sys/conf/kmod.mk:98 resets CFLAGS; COPTS+= must be used.