Hi,

I just ran through this OOPS when I was doing a dpkg dist-upgrade on my
Pentium III. Any idea what could have caused this ?

(by the way, this computer is generally slow since I upgraded to
2.6.23.1. It could be a related symptom...)

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
c54a53cf
*pde = 00000000
Oops: 0002 [#1]
PREEMPT 
Modules linked in: mga_vid fuse rt2570 iptable_filter ip_tables x_tables tun mga drm uhci_hcd 3c59x mii via_agp thermal usbcore button agpgart processor
CPU:    0
   Not tainted VLI
EFLAGS: 00210202   (2.6.23.1 #1)
EIP is at 0xc54a53cf
eax: c54a5344   ebx: c54a5344   ecx: 00000000   edx: c54a5378
esi: 00000000   edi: c54a53ac   ebp: c54a5474   esp: dfedbc34
ds: 007b   es: 007b   fs: 0000  gs: 0033  ss: 0068
Process xmms (pid: 1337, ti=dfeda000 task=e0602000 task.ti=dfeda000)
Stack: c041dcc8 00000001 c54a5344 c54a54b8 c54a5344 c54a5344 c54a54b8 e75b6c00 
       c01f364e 00000000 00000000 c54a5340 c54a54b8 dfedbd54 c01f37c0 00002000 
       00000000 00002000 dfedbd54 c136bb20 00003000 c01f19b2 00002000 00000000 
Call Trace:
__rpc_execute+0x5b/0x21f
nfs_execute_read+0x30/0x3f
nfs_pagein_one+0x99/0xd0
nfs_pageio_doio+0x2e/0x54
nfs_pageio_add_request+0x98/0xa9
readpage_async_filler+0x117/0x134
readpage_async_filler+0x0/0x134
read_cache_pages+0x6a/0xb4
nfs_readpages+0x124/0x173
nfs_pagein_one+0x0/0xd0
nfs_readpages+0x0/0x173
__do_page_cache_readahead+0x19b/0x260
update_curr+0x102/0x12c
ondemand_readahead+0x48/0xee
page_cache_sync_readahead+0x2a/0x2f
do_generic_mapping_read+0xd8/0x3d0
__check_preempt_curr_fair+0x4f/0x7c
generic_file_aio_read+0x152/0x181
file_read_actor+0x0/0xd7
do_sync_read+0x0/0x109
do_sync_read+0xc6/0x109
autoremove_wake_function+0x0/0x33
do_sync_read+0x0/0x109
vfs_read+0xa6/0x128
sys_read+0x41/0x67
syscall_call+0x7/0xb
 =======================
Code: a4 53 4a c5 a4 53 4a c5 c1 cf 50 d7 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 1e 06 00 ...
[ message continues ]

That is a lot of zeros... Did you perchance compile this kernel over NFS
using kernel 2.6.23 or 2.6.23.1? There is a known writeback bug that
results in that kind of corruption. See

   http://bugzilla.kernel.org/show_bug.cgi?id=9315

Cheers
  Trond



-

[ message continues ]

Nope, it was compiled locally on an ext3 partition.

When the oops happened, I was also reading a flac file from an NFS
server using xmms, which is liklely to be what was causing the NFS
traffic.


-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
-

[ message continues ]

Oh, wait.. what am I saying.. my old PIII was way too slow to compile,
so I switched to compile over NFS. The server was a 2.6.17.14 and the
client a 2.6.21.1.

So that may be the problem. I'll recompile locally.

Thanks,


-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
-

[ message continues ]