Fatal user address access from kernel mode from mount_hammer2 at ffffffff8096933f


Fatal trap 12: page fault while in kernel mode
cpuid = 3; lapic id = 3
fault virtual address	= 0x87
fault code		= supervisor read data, page not present
instruction pointer	= 0x8:0xffffffff8096933f
stack pointer	        = 0x10:0xfffff80118368c98
frame pointer	        = 0x10:0xfffff80118368ce8
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 0, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 867
current thread          = pri 6 
kernel: type 12 trap, code=0

CPU3 stopping CPUs: 0x00000037
 stopped
Stopped at      hammer2_pfsalloc+0x5ef: movzbl  0x87(%r13),%eax
db>