Can't unmount NFS - System freezes

[Florian Huber]

Hello ML,
if I try to unmount a NFS-mounted directory my system freezes.
There is neither a error message nor a log entry.

I can't type anymore, but the NUM-Lock LED can still be switched
on/off. The host is also not ping-able.

I also tried different mount options (nfsvers=3, nfsvers=2, default or
even my former 2.4.x settings).

The NFS server is a 2.4.20 machine exporting with rw,async.
The client is using 2.5.71 (same with 2.5.70-mm9).

I'm sorry that I can't give you a more detailed description of the
problem. Perhaps you can give me some hints how to debug this.

TIA
	Florian Huber