Hello,
I'm trying to modify kernel buffers on kernel 4.2.19...
so I added one double type variable in "struct buffer_head" at fs.h
But whenever I compiled and referenced that variable, os even cannot boot and show me kernel panic screen..
error message is:

Partition check:
sda:<1>Unable to handle kernel NULL pointer dereference at virtual address 0000005c
printing eip:
c013a1e9
*pde = 00000000
Oops:0002

and registers, stack, call trace goes.
in my guess, there are fixed size of "struct buffer_head",
so it cannot accept my modification....maybe
or are there something I don't know? I need some help.