Fatal trap 12: page fault while in kernel mode
cpuid = 3; lapic id = 3
fault virtual address	= 0xfffff8021776a200
fault code		= supervisor write data, page not present
instruction pointer	= 0x8:0xffffffff8090243b
stack pointer	        = 0x10:0xfffff8011869f240
frame pointer	        = 0x10:0xfffff8011869f278
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		= 1109
current thread          = pri 6 
kernel: type 12 trap, code=2

CPU3 stopping CPUs: 0x00000037
 stopped
Stopped at      ffs_clusteracct.isra.0+0x1eb:   movl    %eax,(%rdx,%rcx,4)
db>