Doubts in Kernel Debugger

Murali Selvaraj murali.selvaraj2003 at yahoo.com
Thu Sep 4 09:39:23 PDT 2008


 Hello All,
 
            This is my first mail for this mailing list.Actually i have tried to clear my doubt in all forums,but i could not able
to find the solution for my problem.Here i will explain about my issue.
 
           i have some problem in my Linux Machine(2.4.17),it seems one of the application process is become looping.
So i could not able to access my system.So i have tried through kdb mode.After enter into KDB that time only i have found 
current running process(my application process using ps command under KDB). Then i have dumped the memory to dedicated
Crashdump partition.My system having Crashdump Mechanism.
The problem is when i have dump the System memory,all system registers (eax,ebx,........,esp,eip) values like invalid values.
The values all are less than 0xc0000000(PAGE_OFFSET).All values are like user-space values.So my crashdump
mechanism could not able to dump the memory.Because the computation of current process descriptor (esp & 0xffffe000) address
becomes invalid.So i didnt get Kernel Stack for this Process,because of invalid ESP value.
 
        Could you please explain me,in this case how can i dump the corresponding kernel-space values (all pt_regs values)
in kdb mode.Then only i can able to dump the memory properly.After that only i can able to start my Crash analysis.
How to find the pt_regs address for this case,in kernel-space land.
 
        Actually i have modified my part of KDB code like this for this case,
 
                   if ( regs->esp < PAGE_OFFSET)
                   {
                             regs->esp=current->thread.esp;
                             regs->eip=current->thread.eip;
                             regs->ebp=*(unsigned long *)esp;     
                    }
                      Then pass the address of pt_regs for Crashdump Mechanism,i tried this modification in my system,but i couldnt succeeded.
 
            If you have any information  about this one Could you reply to me,it will be very useful.
If my Question is wrong,Could you please ignore it.

Thankx & Regards,
Murali.S


      
---------------------------
Use http://oss.sgi.com/ecartis to modify your settings or to unsubscribe.


More information about the kdb mailing list