Logout from ISCSI Target hangs permanently

["Dominik" <k-ruser@gmx.de>]

Hi,

i´ve got a big issue since the last weeks which i am unable to solve.

First of all some information about my system:

Debian Squeeze
Kernel: 2.6.32-5-xen-amd64
Open-Iscsi-Version: 2.0.871.3-2squeeze1
iscsiadm-Version: 2.0-871
LVM-Version: 2.02.66-5 

I connected an iscsi target with my server and made this to a pv and 
added it to an own, new created volume-group.
Later i used some lv´s on this volume-group.

Everything worked just fine until i stopped/lost connection
 to the iscsi server.
(so far as i know the lv on the iscsi device are not mounted at this moment,
 and also not mounted in any of my xen-domUs)

After the connection was lost, the icsci device is still there, and so my
lvm 
drops errors on every action, as it cannot connect to the volume group:

LVM-Error during #lvscan:

  /dev/sdf: read failed after 0 of 4096 at 0: Eingabe-/Ausgabefehler
  /dev/sdg: read failed after 0 of 4096 at 0: Eingabe-/Ausgabefehler


So i just went to shutdown and deactivate my iscsi device, but the iscsiadm
won´t disconnect the device anymore.
Even the timeout has no effect and no error is printed:

root@xxx-server1:/home/xxx# iscsiadm -m session
tcp: [1] xxx.xxx.xxx.x20:3260,1 iqn.2011-09.icsci1.xxx.de:backup-space2
tcp: [2] xxx.xxx.xxx.x21:3260,1 iqn.2012-07.icsci1.xxx.de:backup-space3

root@xxx-server1:/home/xxx# iscsiadm -m node -u 
Logging out of session [sid: 1, target:
iqn.2011-09.icsci1.xxx.de:backup-space2, portal: xxx.xxx.xxx.x21:3260]
Logging out of session [sid: 2, target:
iqn.2012-07.icsci1.xxx.de:backup-space3, portal: xxx.xxx.xxx.x21:3260]

After that its stuck, and i only can abort the operation with ctrl-c !

Is there a way to force a log out, or kill the iscsi process 
and remove the devices manually,without reboot? 

Unfortunaly I have this problem on two diferent servers
 with exactly the same configuration, connected to the same iscsi target.

I don´t know if it is a Bug in open-iscsi or in lvm or in the combination of
it.
I would of course post a Bug-Report if no one can give me a hint where it
belongs to. 

Thanks for any help!

Greetings
Dominik