Description of problem:
(*Found using vdsm)

after many successful logins to the same target, one login command just hangs forever:

Thread-1873::DEBUG::2011-09-04 14:02:33,847::iscsi::373::Storage.Misc.excCmd::(addiSCSIPortal) '/usr/bin/sudo -n /sbin/iscsiadm -m discoverydb -t sendtargets -p 10.35.64.25:3260 --discover' (cwd None)
Thread-1873::DEBUG::2011-09-04 14:02:33,980::iscsi::373::Storage.Misc.excCmd::(addiSCSIPortal) SUCCESS: <err> = ''; <rc> = 0
Thread-1873::DEBUG::2011-09-04 14:02:33,981::iscsi::471::Storage.Misc.excCmd::(addiSCSINode) '/usr/bin/sudo -n /sbin/iscsiadm -m node -T RUTH1 -l -p 10.35.64.25:3260' (cwd None)

[root@pink-vds2 ~]# iscsiadm -m session
iscsiadm: could not read session targetname: 5
iscsiadm: could not find session info for session16
iscsiadm: No active sessions.

from /var/log/messages:
Sep  4 14:02:33 pink-vds2 kernel: NFS: Cache request denied due to non-unique superblock keys
Sep  4 14:02:34 pink-vds2 kernel: scsi18 : iSCSI Initiator over TCP/IP
Sep  4 14:02:35 pink-vds2 iscsid: Could not set session16 priority. READ/WRITE throughout and latency could be affected.
Sep  4 14:02:35 pink-vds2 iscsid: Received iferror -22: Invalid argument.
Sep  4 14:02:35 pink-vds2 iscsid: Can't create connection.
Sep  4 14:02:35 pink-vds2 iscsid: Received iferror -22: Invalid argument.
Sep  4 14:02:35 pink-vds2 iscsid: can not safely destroy connection 0
Sep  4 14:02:50 pink-vds2 iscsid: Received iferror -22: Invalid argument.
Sep  4 14:02:50 pink-vds2 iscsid: can't bind conn 16:0 to session 16, retcode 1 (2)

[root@pink-vds2 ~]# cat /var/lib/iscsi/nodes/RUTH1/10.35.64.25,3260,1/default 
# BEGIN RECORD 2.0-872
node.name = RUTH1
node.tpgt = 1
node.startup = manual
node.leading_login = No
iface.iscsi_ifacename = default
iface.transport_name = tcp
node.discovery_address = 10.35.64.25
node.discovery_port = 3260
node.discovery_type = send_targets
node.session.initial_cmdsn = 0
node.session.initial_login_retry_max = 4
node.session.xmit_thread_priority = -20
node.session.cmds_max = 128
node.session.queue_depth = 32
node.session.nr_sessions = 1
node.session.auth.authmethod = None
node.session.timeo.replacement_timeout = 120
node.session.err_timeo.abort_timeout = 15
node.session.err_timeo.lu_reset_timeout = 30
node.session.err_timeo.tgt_reset_timeout = 30
node.session.err_timeo.host_reset_timeout = 60
node.session.iscsi.FastAbort = Yes
node.session.iscsi.InitialR2T = No
node.session.iscsi.ImmediateData = Yes
node.session.iscsi.FirstBurstLength = 262144
node.session.iscsi.MaxBurstLength = 16776192
node.session.iscsi.DefaultTime2Retain = 0
node.session.iscsi.DefaultTime2Wait = 2
node.session.iscsi.MaxConnections = 1
node.session.iscsi.MaxOutstandingR2T = 1
node.session.iscsi.ERL = 0
node.conn[0].address = 10.35.64.25
node.conn[0].port = 3260
node.conn[0].startup = manual
node.conn[0].tcp.window_size = 524288
node.conn[0].tcp.type_of_service = 0
node.conn[0].timeo.logout_timeout = 15
node.conn[0].timeo.login_timeout = 15
node.conn[0].timeo.auth_timeout = 45
node.conn[0].timeo.noop_out_interval = 5
node.conn[0].timeo.noop_out_timeout = 5
node.conn[0].iscsi.MaxXmitDataSegmentLength = 0
node.conn[0].iscsi.MaxRecvDataSegmentLength = 131072
node.conn[0].iscsi.HeaderDigest = None
node.conn[0].iscsi.IFMarker = No
node.conn[0].iscsi.OFMarker = No
# END RECORD

Found out that it can be reproduceable with repeated discover -> login-> disconnect:

while true; do /sbin/iscsiadm -m discoverydb -t sendtargets -p 10.35.64.25:3260 --discover; iscsiadm -m node -T TARGET1 -l ; iscsiadm -m node -T TARGET -u; done

After some successful logins, one just hangs forever.

Version-Release number of selected component (if applicable):
iscsi-initiator-utils-6.2.0.872-24.el6.x86_64

Additional info:
Attach strace of the login command.