kernel crash, Tap, OpenvSwitch

Hi,
this is my scenario:

eth0 -> tap1 -> etherswitch -> tap2 -> eth0

it works both in user mode and kernel mode. I make Taps using click.
Now I replace etherswitch element with OpenvSwitch (OVS) which is not a 
click element. it is a kernel module:

eth0 -> tap1 -> OVS -> tap2 -> eth0

It works with usermode Click but in kernel mode the OS crashes once I 
send packets to eth0. I make Taps using OVS.

This is the config:

FromDevice(eth0) -> Queue -> ToDevice(tap1); //it goes to OVS, and will 
be forwarded to tap2
FromDevice(tap2) -> Discard;

If I put each of these lines in a config file and run one in user mode 
and the other in kernel mode, it works fine. but both together in a 
single config file in the kernel mode freezes the OS.
Is that causing a loop?

Any help is appreciated.
Hamid