virtio_pci0: host features: 0x79bf8064 <EventIdx,RingIndirect,AnyLayout,NotifyOnEmpty,SetMacAddress,GuestAnnounce,RxModeExtra,VLanFilter,RxMode,ControlVq,Status,MrgRxBuf,TxAllGSO,MacAddress,DynOffload>
virtio_pci0: negotiated features: 0x198f8020 <RingIndirect,AnyLayout,NotifyOnEmpty,SetMacAddress,VLanFilter,RxMode,ControlVq,Status,MrgRxBuf,MacAddress>
vtnet0: MAC address: 52:54:00:12:34:56
panic: vm_fault: fault on stack guard, addr: 0xfffff8008dd20000
cpuid = 0
Trace beginning at frame 0xfffff801182d8f08
vm_fault() at vm_fault+0x12eb 0xffffffff8099ef9b 
vm_fault() at vm_fault+0x12eb 0xffffffff8099ef9b 
trap_pfault() at trap_pfault+0x9a 0xffffffff80bd52ca 
trap() at trap+0x17c 0xffffffff80bd5bcc 
calltrap() at calltrap+0x9 0xffffffff80b991fa 
--- trap 000000000000000c, rip = ffffffff80bca655, rsp = fffff801182d9310, rbp = fffff801182d93b0 ---
memset() at memset+0xd5 0xffffffff80bca655 
ffs_mount() at ffs_mount+0x9dc 0xffffffff8091210c 
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)