TGT does not support ISER discovery

[Rafael David Tinoco]

[Impact]

 * TGT does not support iSER discovery and suffers from segmentation fault
    whenever a open-iscsi client tries do discover targets using iSER (iSCSI over IB).

[Test Case]

### server (IPoverIB interface IP: 172.16.0.1)

# echo manual > /etc/init/tgt.override
# apt-get install tgt
# tgtd
# tgt-setup-lun -n lunit1 -d /disks/lunit1 -t iser

### client (IPoverIB interface IP: 172.16.0.2)

# apt-get install open-iscsi
# iscsiadm -m discovery --op=show --type sendtargets --portal 172.16.0.1 -I iser

/var/log/syslog:

tgtd: tgtd daemon started, pid:11274
tgtd: tgtd logger started, pid:11275 debug:0
tgtd: work_timer_start(150) use signal based scheduler
tgtd: bs_init(390) use signalfd notification
tgtd: device_mgmt(246) sz:19 params:path=/disks/lunit1
tgtd: bs_thread_open(412) 16
tgtd: iser_alloc_pool(572) shmget rdma pool sz:1073741824 failed
tgtd: iser_cm_conn_established(1615) conn:0x19f06a0 cm_id:0x19f00d0, 172.16.0.2 -> 172.16.0.1, established
kernel: [233439.714120] tgtd[11274] segfault at 0 ip 00007fc36a5b3abf sp 00007ffefb551be0 error 4 in librdmacm.so.1.0.0[7fc36a5ae000+d000]
tgtd: handle_wc_error(2978) conn:0x19fce10 task:0x19f2e60 tag:0x0000 wr_id:0x0x19f2ec0 op:recv err:local protection error vendor_err:0x32
tgtd: tgtd logger exits abnormally, pid:11275

[Regression Potential]

 * Tested multiple times in a Infiniband lab environment provided by Mellanox
 * For open-iscsi to work with iSER kernel 3.16 should be used
 * Watch bug https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1443648 for 3.13 fix on iSER iscsi logout bug (to be fixed)

[Other Info]

Original case: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1443648
Marked as duplicate of this

Upstream commit:

commit 4a4268bc3a458be0190709bdd7f13392f91ca15f
Author: Or Gerlitz <email address hidden>
Date: Tue Jan 28 11:17:59 2014 +0200

    iser: Add Discovery support

    Add support to handle TEXT PDU, such as SendTargets which are used for
    running iscsi discovery over iser.

    Signed-off-by: Or Gerlitz <email address hidden>
    Signed-off-by: Alexander Nezhinsky <email address hidden>
    Signed-off-by: FUJITA Tomonori <email address hidden>

Has to be backported to TGT.

[Rafael David Tinoco (rafaeldtinoco)]

The fix for this bug exposed the kernel problem being fixed in the following bug:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1443648

already fix-committed.

[Rafael David Tinoco (rafaeldtinoco)]

The fix for this bug is contained in another fix in bug:

https://bugs.launchpad.net/ubuntu/trusty/+source/libibverbs/+bug/1409904

So I'm marking this as duplicate.