my 2.5.66-bk9 oops

[hv]

Hi:
When I mount a iso file to /mnt/cdrom,I got this oops.
my kernel is 2.5.66-bk9 and loop is built as a module.

Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
c0389d08
*pde = 00000000
Oops: 0002 [#3]
CPU:    0
EIP:    0060:[<c0389d08>]    Not tainted
EFLAGS: 00010286
eax: 00000000   ebx: f8bd0f4d   ecx: 00000000   edx: ee726000
esi: 00000000   edi: 00000000   ebp: 00000000   esp: f4b3bff8
ds: 007b   es: 007b   ss: 0068
Process mount (pid: 10923, threadinfo=f4b3a000 task=f0125280)
Stack: 00000000 00000000
Call Trace:
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00