Debug Kernel Modules With KGDB

Raghavendra arrao at cdac.in
Mon Dec 1 06:17:14 EST 2014


Hi Zhang,

On Monday 01 December 2014 04:32 PM, Freeman Zhang wrote:
> Hi Raghavendra,
>
> Thanks for your reply, but `sudo` doesn't solve the problem :(
Well then I guess 'sudo' isn't implemented in android. Any way, 
ultimately you may wan't to login as root and then try reading the file 
in order to get the address.
Regards,
Raghavendra
>
> All the best!
>
> Freeman Zhang
>
> -------- Original Message --------
>> On Monday 01 December 2014 03:26 PM, Freeman Zhang wrote:
>>> Hi list,
>>>
>>> I've been trying to setup a debug environment for linux
>>> kernel(v3.4,Android,ARM) with kgdb. It worked fine untill I tried to use
>>> it to debug a module. Under the instruction from LDD, I add module debug
>>> info in gdb with command:
>>>
>>>      add-symbol-file test-module.ko  address
>>>
>>> LDD uses `cat /sys/module/test-module/sections/.text` to get the address
>>> where the module has been loaded. However, I got:
>>>      
>>>      0x00000000
>> Try reading the file as a root.
>> $ sudo cat /sys/module/test-module/sections/.text
>>> When I use `lsmod`, I got:
>>>
>>>      test-module 15278 0 - Live 0x00000000 (O)
>>>
>>> Why nothing but 0x00000000 ??
>>>
>>> So I have to do some research in kernel/module.c, and find out that
>>> struct module -> module_core = 0xbf000000. But when I try these in gdb:
>>>
>>>      add-symbol-file test-module.ko  0xbf000000
>>>      break one_of_my_function
>>>
>>> I got:
>>>
>>>      Cannot access memory at address 0xbf002350
>>>
>>> :(
>>> Could somebody help?
>>>
>>>
>>> All the best!
>>> Freeman Zhang
>>>
>>>      
>>>      
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>> -------------------------------------------------------------------------------------------------------------------------------
>>
>> [ C-DAC is on Social-Media too. Kindly follow us at:
>> Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ]
>>
>> This e-mail is for the sole use of the intended recipient(s) and may
>> contain confidential and privileged information. If you are not the
>> intended recipient, please contact the sender by reply e-mail and destroy
>> all copies and the original message. Any unauthorized review, use,
>> disclosure, dissemination, forwarding, printing or copying of this email
>> is strictly prohibited and appropriate legal action will be taken.
>> -------------------------------------------------------------------------------------------------------------------------------
>>
>>
>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>


-------------------------------------------------------------------------------------------------------------------------------
[ C-DAC is on Social-Media too. Kindly follow us at:
Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ]

This e-mail is for the sole use of the intended recipient(s) and may
contain confidential and privileged information. If you are not the
intended recipient, please contact the sender by reply e-mail and destroy
all copies and the original message. Any unauthorized review, use,
disclosure, dissemination, forwarding, printing or copying of this email
is strictly prohibited and appropriate legal action will be taken.
-------------------------------------------------------------------------------------------------------------------------------




More information about the Kernelnewbies mailing list