2.5.46 oops in __wake_up, from pipe_write

[Duncan Sands]

During system shutdown:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
c01140f0
*pde = 00000000
Oops: 0000
r128 snd-seq-midi snd-seq-midi-event snd-seq snd-usb-audio snd-cs46xx snd-pcm snd-timer snd-rawmidi snd-seq-device snd-ac97-codec snd usbtest uhci-hcd usbcore nls_iso8859-1 nls_cp437 vfat fat rtc  
CPU:    0
EIP:    0060:[<c01140f0>]    Not tainted
EFLAGS: 00010003
EIP is at __wake_up_common+0x10/0x60
eax: c84e2ae0   ebx: c6342000   ecx: 00000001   edx: 00000000
esi: 00000282   edi: 00000001   ebp: c6343f30   esp: c6343f24
ds: 0068   es: 0068   ss: 0068
Process uname (pid: 697, threadinfo=c6342000 task=c65fb3c0)
Stack: c6342000 00000282 00000000 c6343f50 c0114160 c84e2ae0 00000001 00000001 
       00000000 00000007 cb4f5ba0 40012007 c014a3df c6342000 c6342000 cb4f5bfc 
       00000001 00000007 00000007 00000000 c94e0f60 c94e0f60 00000002 c013f906 
Call Trace:
 [<c0114160>] __wake_up+0x20/0x60
 [<c014a3df>] pipe_write+0x1ff/0x2a0
 [<c013f906>] vfs_write+0xa6/0x100
 [<c013fb08>] sys_write+0x28/0x40
 [<c0108f77>] syscall_call+0x7/0xb

Code: 8b 32 74 29 8b 5a f4 8d 42 f4 ff 75 14 ff 75 0c 50 ff 50 08 
 <6>note: uname[697] exited with preempt_count 1