> hi this is mallikarjuna,
>
> please let me clarify this
>
> what is memory leak?


Memory Corruption:
    Freeing or overwriting something that is still is in use.

Memory Leak:
    Not freeing something that is no longer in use.


>how to trace the memory leaks &

There are some tools that allow memory checking, but if you
want to do it manually, this is how you do it in UNIX:

*   Run the top(1) command.  Note down, for Memory and Swap, the
    following items:  total, used, free, and cached.  Do it for
    few times and check

*   If memory usage (shown in %) increases unexpectedly, probably
    that process is causing memory leak.

*   Kill that process.

> can we trace the memory leaks using GDB.
>

I have no idea about this.