Fatal user address access from kernel mode from trigger_retype at ffffffff807f6aa0


Fatal trap 12: page fault while in kernel mode
cpuid = 0; lapic id = 0
fault virtual address	= 0x1
fault code		= supervisor read data, page not present
instruction pointer	= 0x8:0xffffffff807f6aa0
stack pointer	        = 0x10:0xfffff80117f1d668
frame pointer	        = 0x10:0xfffff80117f1d688
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		= 900
current thread          = pri 6 
kernel: type 12 trap, code=0

CPU0 stopping CPUs: 0x0000003e
 stopped
Stopped at      nfs_reclaim+0x150:      movq    (%rdi),%r12
db>