Kernel module to dump Used heap/stack of a user process

Kernel module to dump Used heap/stack of a user process

[Dhyan]

Dear All,

 I am writing a kernel module which will accept  user process id (PID) as
input and dump all the address space of that user process,like  stack,heap
segment.

I took mm->start_brk as start of heap ,mm->brk as end of heap,then i am
seeing, even though user process is not using 33 pages heap size shows as
33 pages
 (mm->brk -mm->start_brk) . (This i verified using /proc/pid/maps) .Stack
also behaves in similar way,

*So is there any way i can find out the really used heap staring from
mm->start_brk,So that i can dump only the used heap*

--
Thanks
Dhyan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120514/c4d326ef/attachment.html 

Kernel module to dump Used heap/stack of a user process

[王哲]

2012/5/14 Dhyan <linuxdhyan@gmail.com>

> Dear All,
>
>  I am writing a kernel module which will accept  user process id (PID) as
> input and dump all the address space of that user process,like  stack,heap
> segment.
>
> I took mm->start_brk as start of heap ,mm->brk as end of heap,then i am
> seeing, even though user process is not using 33 pages heap size shows as
> 33 pages
>  (mm->brk -mm->start_brk) . (This i verified using /proc/pid/maps) .Stack
> also behaves in similar way,
>
> *So is there any way i can find out the really used heap staring from
> mm->start_brk,So that i can dump only the used heap*
>
> --
> Thanks
> Dhyan
>
> I am a kernelnewby and used to write a same kernel module.and hope to help
> you.
>
   please see the link
   http://blog.163.com/zhe_wang_2009/blog/static/17228212120123493614715/

>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120514/45ccd020/attachment.html 

Kernel module to dump Used heap/stack of a user process

[Dhyan]

Thank you wang zhe for a quick reply.
But my problem as like mentioned is to find out the exact used heap size of
the user process instead of total allocated space.

in cat /proc/pid/mpas i am able to see that whenver a user process forks
kernel allocating almost 33 page size of heap.But if the  Process is having
only few dynamic allocation it may be using only few KB heap.


So  i just want to find out the exactly used heap not mm->brk or Vm->end of
heap ,so that i can dump only that portion

if anyone knows please help

Thanks
Dhyan

On Mon, May 14, 2012 at 3:44 PM, ?? <wangzhe5004@gmail.com> wrote:

>
>
> 2012/5/14 Dhyan <linuxdhyan@gmail.com>
>
>> Dear All,
>>
>>  I am writing a kernel module which will accept  user process id (PID) as
>> input and dump all the address space of that user process,like  stack,heap
>> segment.
>>
>> I took mm->start_brk as start of heap ,mm->brk as end of heap,then i am
>> seeing, even though user process is not using 33 pages heap size shows as
>> 33 pages
>>  (mm->brk -mm->start_brk) . (This i verified using /proc/pid/maps) .Stack
>> also behaves in similar way,
>>
>> *So is there any way i can find out the really used heap staring from
>> mm->start_brk,So that i can dump only the used heap*
>>
>> --
>> Thanks
>> Dhyan
>>
>> I am a kernelnewby and used to write a same kernel module.and hope to
>> help you.
>>
>    please see the link
>    http://blog.163.com/zhe_wang_2009/blog/static/17228212120123493614715/
>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120515/50b61d66/attachment.html 

Kernel module to dump Used heap/stack of a user process

[Mulyadi Santosa]

Hi...

On Tue, May 15, 2012 at 10:30 AM, Dhyan <linuxdhyan@gmail.com> wrote:

> But my problem as like mentioned is to find out the exact used heap size of
> the user process instead of total allocated space.

try to check how /proc/<pid>/smaps calculate RSS fields....

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com