[2.5.56] Oops using pppd.

Find attached a decoded kernel oops which I have only _noticed_ since 2.5.56. This is difficult to reproduce, but seems to happen when pppd completes authentication. The connection is dropped immediately.

kobject problems?

Regards,
Alistair Strachan.

ksymoops 2.4.8 on i686 2.5.56. Options used
-V (default)
-k /proc/ksyms (default)
-l /proc/modules (default)
-o /lib/modules/2.5.56/ (default)
-m /boot/System.map-2.5.56 (default)

Warning: You did not tell me where to find symbol information. I will assume that the log matches the kernel and modules that are running right now and I'll use the default options above for symbol resolution. If the current kernel and/or modules do not match the log, you can get more accurate output by telling me the kernel version and where to find map, modules, ksyms etc. ksymoops -h explains the options.

Error (regular_file): read_ksyms stat /proc/ksyms failed No modules in ksyms, skipping objects
No ksyms, skipping lsmod

Call Trace: [<c01ba298>]  [<c02825cb>]  [<c01f9f45>]  [<c01f7c5c>]  [<c01f7b33>]  [<c015ba70>]  [<c015c681>]  [<c010951b>]
Unable to handle kernel NULL pointer dereference at virtual address 0000006c
c0280249
*pde = 00000000
Oops: 0000
CPU:    0
EIP:    0060:[<c0280249>]    Tainted: P

Using defaults from ksymoops -t elf32-i386 -a i386
EFLAGS: 00010216
eax: ffffffff ebx: dc4cff34 ecx: 0000000f edx: 0000006c
esi: 0000006c edi: dc4cff34 ebp: 00000010 esp: dc4cfef4
ds: 007b es: 007b ss: 0068

Stack: dc4ce000 00000001 00008913 dc4cff34 c02802e1 dc4cff34 dc4cff34 00000001
       c02805a3 dc4cff34 dc4ce000 c0282209 dc4cff34 bffff140 00000020 00000000
       30707070 08148d00 bffff168 0060de02 406962fc bffff1a0 00000089 00000012
Call Trace: [<c02802e1>]  [<c02805a3>]  [<c0282209>]  [<c02bb8e6>]  [<c0279315>]  [<c015c681>]  [<c010951b>]
Code: ac ae 75 08 84 c0 75 f5 31 c0 eb 04 19 c0 0c 01 85 c0 74 07

Trace; c01ba298 <kobject_register+58/70>
Trace; c02825cb <register_netdevice+16b/1b0>
Trace; c01f9f45 <ppp_create_interface+125/1d0>
Trace; c01f7c5c <ppp_unattached_ioctl+11c/1d0>
Trace; c01f7b33 <ppp_ioctl+843/850>
Trace; c015ba70 <setfl+c0/f0>
Trace; c015c681 <sys_ioctl+c1/230>
Trace; c010951b <syscall_call+7/b>

Trace; c02802e1 <dev_get+21/50>
Trace; c02805a3 <dev_load+13/60>
Trace; c0282209 <dev_ioctl+a9/2b0>
Trace; c02bb8e6 <inet_ioctl+e6/100>
Trace; c0279315 <sock_ioctl+c5/210>
Trace; c015c681 <sys_ioctl+c1/230>
Trace; c010951b <syscall_call+7/b>

Code; c0280249 <__dev_get_by_name+29/50>
00000000 <_EIP>:
Code; c0280249 <__dev_get_by_name+29/50> <=====
0: ac lods %ds:(%esi),%al <=====
Code; c028024a <__dev_get_by_name+2a/50>
1: ae scas %es:(%edi),%al
Code; c028024b <__dev_get_by_name+2b/50>
2: 75 08 jne c <_EIP+0xc>
Code; c028024d <__dev_get_by_name+2d/50>
4: 84 c0 test %al,%al
Code; c028024f <__dev_get_by_name+2f/50>
6: 75 f5 jne fffffffd <_EIP+0xfffffffd>
Code; c0280251 <__dev_get_by_name+31/50>
8: 31 c0 xor %eax,%eax
Code; c0280253 <__dev_get_by_name+33/50>
a: eb 04 jmp 10 <_EIP+0x10>
Code; c0280255 <__dev_get_by_name+35/50>
c: 19 c0 sbb %eax,%eax
Code; c0280257 <__dev_get_by_name+37/50>
e: 0c 01 or $0x1,%al
Code; c0280259 <__dev_get_by_name+39/50>
10: 85 c0 test %eax,%eax
Code; c028025b <__dev_get_by_name+3b/50>
12: 74 07 je 1b <_EIP+0x1b>

1 warning and 1 error issued. Results may not be reliable.

Badness in kobject_register at lib/kobject.c:129

Call Trace: [<c01ba298>]  [<c02825cb>]  [<c01f9f45>]  [<c01f7c5c>]  [<c01f7b33>]  [<c015ba70>]  [<c015c681>]  [<c010951b>]
PPP: couldn't register device ppp0 (-17)
Unable to handle kernel NULL pointer dereference at virtual address 0000006c
 printing eip:
c0280249
*pde = 00000000
Oops: 0000
CPU:    0
EIP:    0060:[<c0280249>]    Tainted: P
EFLAGS: 00010216
eax: ffffffff   ebx: dc4cff34   ecx: 0000000f   edx: 0000006c
esi: 0000006c   edi: dc4cff34   ebp: 00000010   esp: dc4cfef4
ds: 007b   es: 007b   ss: 0068
Process kppp (pid: 370, threadinfo=dc4ce000 task=dd5d2d20)
Stack: dc4ce000 00000001 00008913 dc4cff34 c02802e1 dc4cff34 dc4cff34 00000001
       c02805a3 dc4cff34 dc4ce000 c0282209 dc4cff34 bffff140 00000020 00000000
       30707070 08148d00 bffff168 0060de02 406962fc bffff1a0 00000089 00000012
Call Trace: [<c02802e1>]  [<c02805a3>]  [<c0282209>]  [<c02bb8e6>]  [<c0279315>]  [<c015c681>]  [<c010951b>]
Code: ac ae 75 08 84 c0 75 f5 31 c0 eb 04 19 c0 0c 01 85 c0 74 07
 <6>note: kppp[370] exited with preempt_count 1
Unable to handle kernel paging request at virtual address 64203361
 printing eip:
c0280249
*pde = 00000000
Oops: 0000
CPU:    0
EIP:    0060:[<c0280249>]    Tainted: P
EFLAGS: 00010216
eax: ffffffff   ebx: c6831f34   ecx: 0000000f   edx: 64203361
esi: 64203361   edi: c6831f34   ebp: 00000010   esp: c6831ef4
ds: 007b   es: 007b   ss: 0068
Process kppp (pid: 631, threadinfo=c6830000 task=d873a1a0)
Stack: c6830000 00000001 00008913 c6831f34 c02802e1 c6831f34 c6831f34 00000001
       c02805a3 c6831f34 c6830000 c0282209 c6831f34 bfffe5a0 00000020 00000000
       30707070 00000200 080d67e0 00ffe5e0 bfffef78 4000aa80 bfffe5d4 00005410
Call Trace: [<c02802e1>]  [<c02805a3>]  [<c0282209>]  [<c02bb8e6>]  [<c0279315>]  [<c015c681>]  [<c010951b>]
Code: ac ae 75 08 84 c0 75 f5 31 c0 eb 04 19 c0 0c 01 85 c0 74 07
 <6>note: kppp[631] exited with preempt_count 1
Unable to handle kernel paging request at virtual address 0007003e
 printing eip:
c0280249
*pde = 00000000
Oops: 0000
CPU:    0
EIP:    0060:[<c0280249>]    Tainted: P
EFLAGS: 00010216
eax: 00000001   ebx: c7925f34   ecx: 0000000f   edx: 0007003e
esi: 0007003e   edi: c7925f34   ebp: 00000010   esp: c7925ef4
ds: 007b   es: 007b   ss: 0068
Process kppp (pid: 632, threadinfo=c7924000 task=d873a1a0)
Stack: c7924000 00000001 00008913 c7925f34 c02802e1 c7925f34 c7925f34 00000001
       c02805a3 c7925f34 c7924000 c0282209 c7925f34 bffff130 00000020 00000000
       30707070 081ba300 bffff158 0060de02 406962fc bffff190 00000089 00000012
Call Trace: [<c02802e1>]  [<c02805a3>]  [<c0282209>]  [<c02bb8e6>]  [<c0279315>]  [<c015c681>]  [<c0119aa0>]  [<c010951b>]
Code: ac ae 75 08 84 c0 75 f5 31 c0 eb 04 19 c0 0c 01 85 c0 74 07
 <6>note: kppp[632] exited with preempt_count 1
Unable to handle kernel paging request at virtual address 0006000a
 printing eip:
c0280249
*pde = 00000000
Oops: 0000
CPU:    0
EIP:    0060:[<c0280249>]    Tainted: P
EFLAGS: 00010216
eax: ffffffff   ebx: c2cbff34   ecx: 0000000f   edx: 0006000a
esi: 0006000a   edi: c2cbff34   ebp: 00000010   esp: c2cbfef4
ds: 007b   es: 007b   ss: 0068
Process kppp (pid: 640, threadinfo=c2cbe000 task=c8d16140)
Stack: c2cbe000 00000001 00008913 c2cbff34 c02802e1 c2cbff34 c2cbff34 00000001
       c02805a3 c2cbff34 c2cbe000 c0282209 c2cbff34 bfffe590 00000020 00000000
       30707070 00000200 080d67e0 00ffe5d0 bfffef68 4000aa80 bfffe5c4 00005410
Call Trace: [<c02802e1>]  [<c02805a3>]  [<c0282209>]  [<c02bb8e6>]  [<c0279315>]  [<c015c681>]  [<c010951b>]
Code: ac ae 75 08 84 c0 75 f5 31 c0 eb 04 19 c0 0c 01 85 c0 74 07
 <6>note: kppp[640] exited with preempt_count 1

As a counter example, I'm running pppoe with pppd 2.4.2b1 and the rp-pppoe.so plugin with pap authentication under 2.5.56 right now. Granted this doesn't use a physical serial port, but it does exercise de ppp driver and pap authentication.