diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 9835a89a221e7c8242f603b17cd4b061d2e793a2..896f5e96a7b1eec1414cd0a456a1e70cf928a4a1 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -828,7 +828,7 @@ EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
  * @datalen: len of buffer
  *
  * iscsi_cmd_rsp sets up the scsi_cmnd fields based on the PDU and
- * then completes the command and task.
+ * then completes the command and task. called under back_lock
  **/
 static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 			       struct iscsi_task *task, char *data,
@@ -931,6 +931,9 @@ static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
  * @conn: iscsi connection
  * @hdr:  iscsi pdu
  * @task: scsi command task
+ *
+ * iscsi_data_in_rsp sets up the scsi_cmnd fields based on the data received
+ * then completes the command and task. called under back_lock
  **/
 static void
 iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
@@ -1015,6 +1018,16 @@ static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
 	return 0;
 }
 
+/**
+ * iscsi_nop_out_rsp - SCSI NOP Response processing
+ * @task: scsi command task
+ * @nop: the nop structure
+ * @data: where to put the data
+ * @datalen: length of data
+ *
+ * iscsi_nop_out_rsp handles nop response from use or
+ * from user space. called under back_lock
+ **/
 static int iscsi_nop_out_rsp(struct iscsi_task *task,
 			     struct iscsi_nopin *nop, char *data, int datalen)
 {
@@ -1787,7 +1800,9 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
 	return 0;
 
 prepd_reject:
+	spin_lock_bh(&session->back_lock);
 	iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
+	spin_unlock_bh(&session->back_lock);
 reject:
 	spin_unlock_bh(&session->frwd_lock);
 	ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
@@ -1795,7 +1810,9 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
 	return SCSI_MLQUEUE_TARGET_BUSY;
 
 prepd_fault:
+	spin_lock_bh(&session->back_lock);
 	iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
+	spin_unlock_bh(&session->back_lock);
 fault:
 	spin_unlock_bh(&session->frwd_lock);
 	ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
@@ -3117,8 +3134,9 @@ fail_mgmt_tasks(struct iscsi_session *session, struct iscsi_conn *conn)
 		state = ISCSI_TASK_ABRT_SESS_RECOV;
 		if (task->state == ISCSI_TASK_PENDING)
 			state = ISCSI_TASK_COMPLETED;
+		spin_lock_bh(&session->back_lock);
 		iscsi_complete_task(task, state);
-
+		spin_unlock_bh(&session->back_lock);
 	}
 }