Debugging PPPD Resource Leaks

Joel Sherrill joel.sherrill at
Sat Oct 6 15:47:12 UTC 2001

> Mike Siers wrote:
> Hi,
> I have a simple test program that should run forever but
> it stops functioning correctly after about 20 iterations.
> What is the best way to debug resource leaks?  Do
> the following gdb commands still work correctly to display
> available Workspace and Heap memory?
>   print *(Heap_Block *)_Workspace_Area->first
>   print *((Region_Control
> *)_Region_Information->local_table[1])->Memory->first

This is insufficient.  You can trace these chains fown
but this is only the first block

You might want to look at libc/mallocfreespace.c
and provide a similar entry to get all the information you can from
the underlying heap (# of used/free blocks and total used/free memory).

> The program is just trying to bring up and down a ppp link
> over a direct serial cable.  It works about 20 times and then
> it can not successfully bring up the IP layer.  What things can
> I look at to help determine if the network stack has run out
> of memory?

The stack has its own memory issues which might be a factor.
There is a routine to print out net stats which I don't remember
offhand which might be helpful.

> I am using the current snapshot.  Any debugging hints/tips
> would be greatly appreciated.
> Thanks
> Mike Siers

Joel Sherrill, Ph.D.             Director of Research & Development
joel at                 On-Line Applications Research
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