$ dfbsd-qemu/vm.sh run_root 'kldload /tmp/seg-overflow.ko; echo RC=$?'
(run_root produced no output before the guest died; RC never printed)
$ dfbsd-qemu/vm.sh log 25   [t=+8s after kldload]
Fatal trap 12: page fault while in kernel mode
cpuid = 3; lapic id = 3
fault virtual address  = 0xfffff80116e69000
fault code             = supervisor write data, page not present
instruction pointer    = 0x8:0xffffffff80bcaa0a
stack pointer          = 0x10:0xfffff8011831b480
frame pointer          = 0x10:0xfffff8011831b4d8
processor eflags       = interrupt enabled, resume, IOPL = 0
current process        = 835         (kldload)
kernel: type 12 trap, code=2

CPU3 stopping CPUs: 0x00000037
 stopped
Stopped at      memmove+0x10a:       repe movsq      (%rsi),%es:(%rdi)
db>