iscsi-target: Make TASK_REASSIGN use proper se_cmd->cmd_kref

Since commit 59b6986dbf fixed a potential NULL pointer dereference
by allocating a se_tmr_req for ISCSI_TM_FUNC_TASK_REASSIGN, the
se_tmr_req is currently leaked by iscsit_free_cmd() because no
iscsi_cmd->se_cmd.se_tfo was associated.

To address this, treat ISCSI_TM_FUNC_TASK_REASSIGN like any other
TMR and call transport_init_se_cmd() + target_get_sess_cmd() to
setup iscsi_cmd->se_cmd.se_tfo with se_cmd->cmd_kref of 2.

This will ensure normal release operation once se_cmd->cmd_kref
reaches zero and target_release_cmd_kref() is invoked, se_tmr_req
will be released via existing target_free_cmd_mem() and
core_tmr_release_req() code.

Reported-by: Donald White <dew@datera.io>
Cc: Donald White <dew@datera.io>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 9 insertions, 13 deletions

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 541f66a875fc..048d4227327c 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -1955,7 +1955,6 @@ iscsit_handle_task_mgt_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
         struct iscsi_tmr_req *tmr_req;
         struct iscsi_tm *hdr;
         int out_of_order_cmdsn = 0, ret;
-        bool sess_ref = false;
         u8 function, tcm_function = TMR_UNKNOWN;
 
         hdr                     = (struct iscsi_tm *) buf;
@@ -1988,22 +1987,23 @@ iscsit_handle_task_mgt_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 
         cmd->data_direction = DMA_NONE;
         cmd->tmr_req = kzalloc(sizeof(*cmd->tmr_req), GFP_KERNEL);
-        if (!cmd->tmr_req)
+        if (!cmd->tmr_req) {
                 return iscsit_add_reject_cmd(cmd,
                                              ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                              buf);
+        }
+
+        transport_init_se_cmd(&cmd->se_cmd, &iscsi_ops,
+                              conn->sess->se_sess, 0, DMA_NONE,
+                              TCM_SIMPLE_TAG, cmd->sense_buffer + 2);
+
+        target_get_sess_cmd(&cmd->se_cmd, true);
 
         /*
          * TASK_REASSIGN for ERL=2 / connection stays inside of
          * LIO-Target $FABRIC_MOD
          */
         if (function != ISCSI_TM_FUNC_TASK_REASSIGN) {
-                transport_init_se_cmd(&cmd->se_cmd, &iscsi_ops,
-                                      conn->sess->se_sess, 0, DMA_NONE,
-                                      TCM_SIMPLE_TAG, cmd->sense_buffer + 2);
-
-                target_get_sess_cmd(&cmd->se_cmd, true);
-                sess_ref = true;
                 tcm_function = iscsit_convert_tmf(function);
                 if (tcm_function == TMR_UNKNOWN) {
                         pr_err("Unknown iSCSI TMR Function:"
@@ -2119,12 +2119,8 @@ attach:
          * For connection recovery, this is also the default action for
          * TMR TASK_REASSIGN.
          */
-        if (sess_ref) {
-                pr_debug("Handle TMR, using sess_ref=true check\n");
-                target_put_sess_cmd(&cmd->se_cmd);
-        }
-
         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
+        target_put_sess_cmd(&cmd->se_cmd);
         return 0;
 }
 EXPORT_SYMBOL(iscsit_handle_task_mgt_cmd);