iscsi-target: Fix panic when adding second TCP connection to iSCSI session

In MC/S scenario, the conn->sess has been set NULL in
iscsi_login_non_zero_tsih_s1 when the second connection comes here,
then kernel panic.

The conn->sess will be assigned in iscsi_login_non_zero_tsih_s2. So
we should check whether it's NULL before calling.

Signed-off-by: Feng Li <lifeng1519@gmail.com>
Tested-by: Sumit Rai <sumit.rai@calsoftinc.com>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index b5212f0f9571..adf419fa4291 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -1371,8 +1371,9 @@ static int __iscsi_target_login_thread(struct iscsi_np *np)
         }
         login->zero_tsih = zero_tsih;
 
-        conn->sess->se_sess->sup_prot_ops =
-                conn->conn_transport->iscsit_get_sup_prot_ops(conn);
+        if (conn->sess)
+                conn->sess->se_sess->sup_prot_ops =
+                        conn->conn_transport->iscsit_get_sup_prot_ops(conn);
 
         tpg = conn->tpg;
         if (!tpg) {