Re: kernel module debugging question

Re: kernel module debugging question

[Arjan van de Ven]

On Fri, 2006-06-30 at 12:28 +0000, s.a. wrote:
> Hi,
> I have got the following fault , can you provide me with more details
> about the problem ?
> Best Regards

Hi,

you disabled CONFIG_KALLSYMS in your kernel configuration, which means
the backtrace isn't really useful for anyone to look at (unless you run
ksymoops with the exact System.map)... the problem is that it only shows
the addresses of the bad guys, but not the names. Those addresses are
different for each compilation, and you can use YOUR System.map file to
decode. However it's a lot more robust to let the kernel decode it for
you by enabling CONFIG_KALLSYMS....

Greetings,
    Arjan van de Ven

kernel module debugging question

[s.a.]

Hi,
I have got the following fault , can you provide me with more details
about the problem ?
Best Regards
Steph

general protection fault: 0000 [#1]
PREEMPT
Modules linked in: nls_iso8859_1 nls_cp437 i915 rtcan_sja1000 e100
usb_storage eepro100 mii rtc unix
CPU:    0
EIP:    0060:[<c0103112>]    Not tainted VLI
EFLAGS: 00010246   (2.6.16.19-ipipe #1)
EIP is at sysenter_exit+0xf/0x11
eax: 00000010   ebx: 00000000   ecx: b7d1223c   edx: ffffe410
esi: b7d122cc   edi: 00000000   ebp: 00000000   esp: dc1a7fbc
ds: 007b   es: 007b   ss: 0068
Process EnvoiPDO0 (pid: 1879, threadinfo=dc1a6000 task=de35d030)
Stack: <0>00000000 b7d122cc 00000000 b7d122cc 00000000 b7d12268 00000010
0000007b
       0000007b 0802022b ffffe410 00000073 00000206 b7d1223c 0000007b
00000000
       00000000
Call Trace:
Code: 44 24 18 e8 81 ca 03 00 fb 8b 4d 08 66 f7 c1 ff fe 0f 85 4e 01 00
00 e8 ed ea 00 00 8b 44 24 18 8b 54 24 28 8b 4c 24 34 31 ed fb <0f> 35
50 fc 06 1e 50 55 57 56 52 51 53 ba 7b 00 00 00 8e da 8e
 <0>general protection fault: 0000 [#2]
PREEMPT
Modules linked in: nls_iso8859_1 nls_cp437 i915 rtcan_sja1000 e100
usb_storage eepro100 mii rtc unix
CPU:    0
EIP:    0060:[<c0103112>]    Not tainted VLI
EFLAGS: 00010246   (2.6.16.19-ipipe #1)
EIP is at sysenter_exit+0xf/0x11
eax: 00000000   ebx: 00000000   ecx: b7ce6a2c   edx: ffffe410
esi: 00669627   edi: 00000000   ebp: 00000000   esp: d704ffbc
ds: 007b   es: 007b   ss: 0068
Process Automat (pid: 1882, threadinfo=d704e000 task=d701b030)
Stack: <0>00000000 00000001 b7d8a660 00669627 00000000 b7ce6a58 00000000
2801007b
       0000007b 0801022b ffffe410 00000073 00000206 b7ce6a2c 0000007b
00000000
       00000000
Call Trace:
Code: 44 24 18 e8 81 ca 03 00 fb 8b 4d 08 66 f7 c1 ff fe 0f 85 4e 01 00
00 e8 ed ea 00 00 8b 44 24 18 8b 54 24 28 8b 4c 24 34 31 ed fb <0f> 35
50 fc 06 1e 50 55 57 56 52 51 53 ba 7b 00 00 00 8e da 8e
 

Re: kernel module debugging question

[Chuck Ebbert]

In-Reply-To: <1151661642.11434.23.camel@laptopd505.fenrus.org>

On Fri, 30 Jun 2006 12:00:42 +0200, Arjan van de Ven wrote:

> On Fri, 2006-06-30 at 12:28 +0000, s.a. wrote:
> > Hi,
> > I have got the following fault , can you provide me with more details
> > about the problem ?
> > Best Regards
> 
> you disabled CONFIG_KALLSYMS in your kernel configuration, which means
> the backtrace isn't really useful for anyone to look at

The only thing on the stack is the regs, thus no backtrace.

Someone modified entry.S and added code just before the sysexit.  There is
no 'sysenter_exit' in stock 2.6.16 for one, and there's new code before
the sysexit:

   3:   e8 81 ca 03 00            call   3ca89 <_EIP+0x3ca89> <== new
   8:   fb                        sti                       <== new
   9:   8b 4d 08                  mov    0x8(%ebp),%ecx
   c:   66 f7 c1 ff fe            test   $0xfeff,%cx
  11:   0f 85 4e 01 00 00         jne    165 <_EIP+0x165>
  17:   e8 ed ea 00 00            call   eb09 <_EIP+0xeb09> <== new
  1c:   8b 44 24 18               mov    0x18(%esp),%eax <== new
  20:   8b 54 24 28               mov    0x28(%esp),%edx
  24:   8b 4c 24 34               mov    0x34(%esp),%ecx
  28:   31 ed                     xor    %ebp,%ebp
  2a:   fb                        sti
   0:   0f 35                     sysexit    <===== oops

But that doesn't explain the oops.  Maybe the SYSENTER MSR got screwed up?

-- 
Chuck
 "You can't read a newspaper if you can't read."  --George W. Bush