(fix attempt 2 = mp_token in mutators; guest /usr/src patched, then:)
$ cd /usr/src && make -j6 nativekernel   [log /tmp/kbuild3.log, pre-reboot]
  -> grep -c "error:" /tmp/kbuild3.log  => 0
  -> --------------------------------------------------------------
  -> >>> Kernel build for X86_64_GENERIC completed on Sat Sep 12 13:29:44 UTC 2026
  -> --------------------------------------------------------------
$ make installkernel
  -> >>> Kernel install for X86_64_GENERIC completed on Sat Sep 12 13:31:42 UTC 2026
$ reboot; uname -a =>
DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #1: Sat Sep 12 13:26:06 UTC 2026
    root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64
(fix attempt 1 = dedicated encap_token in walkers+mutators: build OK, but the
patched kernel itself panicked on the race run - see fix.attempt1.failed.txt)