2.6.3: NULL pointer deref in get_disk()

2.6.3: NULL pointer deref in get_disk()

[Calum Mackay]

I've recently started seeing the following on every attempt to mount a 
CompactFlash card - with a VFAT fs on it.

I am pretty sure that I've been able to mount this CF card previously, 
with the same 2.6.3 kernel, and in fact even during this boot uptime.

any thoughts?

cheers,
c.

diz $ mount -V
mount: mount-2.12
diz $ uname -a
Linux diz 2.6.3 #16 Fri Feb 20 13:48:22 GMT 2004 i686 GNU/Linux

Feb 28 11:11:18 cdmnet kernel:  <1>Unable to handle kernel NULL pointer 
dereference at virtual address 00000804
Feb 28 11:11:18 cdmnet kernel:  printing eip:
Feb 28 11:11:18 cdmnet kernel: c01e94a2
Feb 28 11:11:18 cdmnet kernel: *pde = 00000000
Feb 28 11:11:18 cdmnet kernel: Oops: 0000 [#1831]
Feb 28 11:11:18 cdmnet kernel: CPU:    0
Feb 28 11:11:18 cdmnet kernel: EIP:    0060:[get_disk+18/168]    Not tainted
Feb 28 11:11:18 cdmnet kernel: EFLAGS: 00210206
Feb 28 11:11:18 cdmnet kernel: EIP is at get_disk+0x12/0xa8
Feb 28 11:11:18 cdmnet kernel: eax: 000007f0   ebx: edd96a80   ecx: 
00000008   edx: 00000001
Feb 28 11:11:18 cdmnet kernel: esi: 00000000   edi: edd96a80   ebp: 
c01e8e2c   esp: cf719c54Feb 28 11:11:18 cdmnet kernel: ds: 007b   es: 
007b   ss: 0068
Feb 28 11:11:18 cdmnet kernel: Process mount (pid: 13879, 
threadinfo=cf718000 task=e4190ce0)
Feb 28 11:11:18 cdmnet kernel: Stack: edd96a80 00000000 d1d3ef40 
c01e8e42 edd96a80 c01e3bd7 00800001 edd96a80
Feb 28 11:11:18 cdmnet kernel:        cf718000 e60c1180 e60c1180 
00000001 0000000f c01e8ecd efd2c800 00800001
Feb 28 11:11:18 cdmnet kernel:        cf719cc0 c0151c32 00800001 
cf719cc0 00000000 e60c1180 cf719de0 00000001
Feb 28 11:11:18 cdmnet kernel: Call Trace:
Feb 28 11:11:18 cdmnet kernel:  [exact_lock+10/32] exact_lock+0xa/0x20
Feb 28 11:11:19 cdmnet kernel:  [kobj_lookup+199/444] kobj_lookup+0xc7/0x1bc
Feb 28 11:11:19 cdmnet kernel:  [get_gendisk+21/44] get_gendisk+0x15/0x2c
Feb 28 11:11:19 cdmnet kernel:  [do_open+70/988] do_open+0x46/0x3dc
Feb 28 11:11:19 cdmnet kernel:  [blkdev_get+109/124] blkdev_get+0x6d/0x7c
Feb 28 11:11:19 cdmnet kernel:  [open_bdev_excl+66/140] 
open_bdev_excl+0x42/0x8c
Feb 28 11:11:19 cdmnet kernel:  [get_sb_bdev+29/304] get_sb_bdev+0x1d/0x130
Feb 28 11:11:19 cdmnet kernel:  [kmem_cache_alloc+47/56] 
kmem_cache_alloc+0x2f/0x38
Feb 28 11:11:19 cdmnet kernel:  [__crc_do_softirq+304176/2176560] 
gcc2_compiled.+0x1f/0x24 [vfat]
Feb 28 11:11:19 cdmnet kernel:  [__crc_do_softirq+304069/2176560] 
vfat_fill_super+0x0/0x4c [vfat]
Feb 28 11:11:19 cdmnet kernel:  [do_kern_mount+74/180] 
do_kern_mount+0x4a/0xb4
Feb 28 11:11:19 cdmnet kernel:  [do_add_mount+105/312] 
do_add_mount+0x69/0x138
Feb 28 11:11:19 cdmnet kernel:  [do_mount+354/380] do_mount+0x162/0x17c
Feb 28 11:11:19 cdmnet kernel:  [copy_mount_options+128/248] 
copy_mount_options+0x80/0xf8
Feb 28 11:11:19 cdmnet kernel:  [sys_mount+167/276] sys_mount+0xa7/0x114
Feb 28 11:11:19 cdmnet kernel:  [sysenter_past_esp+82/113] 
sysenter_past_esp+0x52/0x71
Feb 28 11:11:19 cdmnet kernel:
Feb 28 11:11:19 cdmnet kernel: Code: 8b 70 14 85 f6 74 3b bb 01 00 00 00 
b8 00 e0 ff ff 21 e0 ff