Unable to handle kernel NULL pointer dereference at virtual address 00000028
 printing eip:
c02298bb
*pde = 00000000
Oops: 0002
CPU:    0
EIP:    0060:[<c02298bb>]    Not tainted
EFLAGS: 00010282
EIP is at loop_get_buffer+0x5b/0x70
eax: 00000000   ebx: c0511160   ecx: c0511120   edx: c7fec910
esi: c114a000   edi: c114a110   ebp: c5af7a2c   esp: c5af7a18
ds: 007b   es: 007b   ss: 0068
Process dd (pid: 221, threadinfo=c5af6000 task=c748a6c0)
Stack: c0511160 00000010 00000001 c114a000 00000001 c5af7a50 c0229b06 c114a000 
       c0511160 c7feee20 00000000 c7ed13c0 00000001 c114a110 c5af7a84 c021d83d 
       c114a110 c0511160 00000010 00000001 c5af7a6c 00000000 c61fc460 0000513b 
Call Trace:
 [<c0229b06>] loop_make_request+0xd6/0x170
 [<c021d83d>] generic_make_request+0x13d/0x1d0
 [<c021d90d>] submit_bio+0x3d/0x80
 [<c01529c7>] __block_write_full_page+0x207/0x3e0
 [<c0154125>] block_write_full_page+0xd5/0xe0
 [<c0156d20>] blkdev_get_block+0x0/0x60
 [<c0156e80>] blkdev_writepage+0x20/0x30
 [<c0156d20>] blkdev_get_block+0x0/0x60
 [<c013e86c>] shrink_list+0x3cc/0x610
 [<c0124815>] add_timer+0x95/0xb0
 [<c013d679>] __pagevec_release+0x29/0x40
 [<c013ec0a>] shrink_cache+0x15a/0x2d0
 [<c013f39e>] shrink_caches+0x9e/0xc0
 [<c013f435>] try_to_free_pages+0x75/0xe0
 [<c0138f28>] __alloc_pages+0x1b8/0x2c0
 [<c0137b03>] __grab_cache_page+0x43/0xa1
 [<c0137018>] generic_file_aio_write_nolock+0x228/0x7b0
 [<c021bd58>] blk_rq_map_sg+0xf8/0x170
 [<c02464a9>] __ide_dma_begin+0x39/0x50
 [<c0137618>] generic_file_write_nolock+0x78/0x90
 [<c012d1d8>] rcu_process_callbacks+0xe8/0x110
 [<c01212e6>] tasklet_action+0x46/0x70
 [<c010bce8>] do_IRQ+0x108/0x130
 [<c010a6e0>] common_interrupt+0x18/0x20
 [<c0157ea3>] blkdev_file_write+0x33/0x40
 [<c014fb3f>] vfs_write+0xaf/0x120
 [<c014fc4c>] sys_write+0x3c/0x60
 [<c010a573>] syscall_call+0x7/0xb

Code: c7 40 28 d0 97 22 c0 89 c2 89 58 30 eb b1 8d b4 26 00 00 00