There are two possible causes for this kernel memory leak.
There's a bug in the volume management device driver that when
unloaded leaks memory: fix with patch 101907-05 (sparc) or
101908-07 (x86). This bug especially affects systems not
running vold, as it is triggered when the kernel decides to
unload unused device drivers.
The NFS client cache will cache too much. A simple workaround is to
add ``set nrnode = 1000'' to /etc/system and reboot. You may want
to make this larger or smaller depending on how much memory you
have. A good rule of thumb is about 20-30 rnodes per MB of
Another possible candidate is an overflow in /tmp or other
swap based (tmpfs) filesystems. Check with df/du.