Guest (dfbsd-qemu/vm.sh, snapshot "with-src" after final reset):
  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
  kernel config X86_64_GENERIC (INVARIANTS compiled in: debug.spin_lock_test exists)
  6 vCPU (QEMU/KVM -smp 6), 4096 MB RAM, virtio disk/net, console: sio0 + sc0
  dumpdev configured: dumpon: crash dumps to /dev/vbd0s1b
  vmm_guest=1 -> debug.indefinite_uses_rdtsc forced 0 at boot
                (spinlock_sysinit, kern_spinlock.c:377-383)

Sysctl state at test time (defaults):
  debug.lock_test_mode = 0
  debug.debugger_on_panic = 1 (run1/run3), 0 (run2)
  debug.spin_backoff_max = 4096, debug.spin_window_shift = 8

Unprivileged user: maxx (uid 1000); sysctl write denied
  (caps_priv_check_self(SYSCAP_RESTRICTEDROOT), kern_spinlock.c:409)

Audit-tree source: sys/kern/kern_spinlock.c @ repo HEAD (single squashed
commit 6cc80ee9); identical to upstream master for the relevant hunks
(checked 2026-09-03 via github.com/DragonFlyBSD/DragonFlyBSD raw).