memory leak problem on devn-8260?

Customer has modified the devn-8260 driver for
the Power PC 8260FADS reference design, to work
with the additional 2 ports available on the
ECOM board. These changes center around
addressability issues (getting the ports
mapped into an unused space),
and does not modify the core functionality of the driver.
The BSP from the PE 6.2.0 is used (without
Patch A).

They are seeing what appears to be a memory leak,
as the memory usage (shown by pidin) by io-net
grows to about 3MB per thread, and stays at that level.
Eventually the driver dies. (About 2 days)

Using the standard driver, but making only
between 512k and 1MB RAM available, the standard
driver also dies after some time.

On an x86 platform, or using the standard 8260 driver,
the typical memory usage seems to flucuate up
and down.

Any ideas where to look for this, or how to look for this?
Any known issues around the environment ?

Thanks in advance.