panic: assertion "obj != NULL" failed in vm_object_hold_shared at /usr/src/sys/vm/vm_object.c:330
cpuid = 3
Trace beginning at frame 0xfffff80117f151a8
vm_object_hold_shared() at vm_object_hold_shared+0x3f 0xffffffff809ab9bf 
vm_object_hold_shared() at vm_object_hold_shared+0x3f 0xffffffff809ab9bf 
vm_fault() at vm_fault+0x408 0xffffffff8099e0b8 
trap_pfault() at trap_pfault+0x9a 0xffffffff80bd52ca 
trap() at trap+0x17c 0xffffffff80bd5bcc 
calltrap() at calltrap+0x9 0xffffffff80b991fa 
--- trap 000000000000000c, rip = ffffffff80616581, rsp = fffff80117f155c0, rbp = fffff80117f15638 ---
isofntrans() at isofntrans+0xe1 0xffffffff80616581 
Debugger("panic")

CPU3 stopping CPUs: 0x00000037
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>