DF-0056 panic signature (from dfbsd-qemu/boot.log):
Fatal trap 12: page fault while in kernel mode
cpuid = 0; lapic id = 0
fault virtual address	= 0xfffff8011891f000
fault code		= supervisor write data, page not present
instruction pointer	= 0x8:0xffffffff80bcaa0a
stack pointer	        = 0x10:0xfffff801171bb4e0
frame pointer	        = 0x10:0xfffff801171bb538
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 1204
current thread          = pri 6 
kernel: type 12 trap, code=2

CPU0 stopping CPUs: 0x0000003e
 stopped
Stopped at      memmove+0x10a:  repe movsq      (%rsi),%es:(%rdi)
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