[stx-metal] No need to json_object_put for those json_obj created by json_object_object_get_ex.

[Yan Chen]

Title
-----
[stx-metal] No need to json_object_put for those json_obj created by json_object_object_get_ex.

Brief Description
-----------------
Source Code: mtce-common/src/common/jsonUtil.cpp
There is no need to manually adjust reference counts through the json_object_put(), for those json_obj created by json_object_object_get_ex().
This is stated in the json_object.h of json-c, both 0.11 and the latest version.
But on 0.11, json_object_put() will not assert for the ref_count issue, while on the latest version it will.
It is not an urgent issue, but we'd better fix it to follow the json-c spec.

Severity
--------
Critical

Steps to Reproduce
------------------
Run mtcAgent with new version json-c library (test version 0.13.1).

Expected Behavior
------------------
mtcAgent should work properly.

Actual Behavior
----------------
Crashed with assersion:
mtcAgent: json_object.c:189: json_object_put: Assertion `jso->_ref_count > 0' failed.

Reproducibility
---------------
Run mtcAgent with json-c version 0.13.1.

System Configuration
--------------------
json-c version 0.13.1

Branch/Pull Time/Commit
-----------------------
master

Timestamp/Logs
--------------
2018-12-06T16:24:48.468 [25084.00057] localhost mtcAgent mtc mtcNodeCtrl.cpp ( 963) _self_provision : Info : My Hostname : controller-0
2018-12-06T16:24:48.544 [25084.00058] controller-0 mtcAgent com nodeUtil.cpp ( 439) get_ip_addresses : Info : Local IP : 2001:db8::2
2018-12-06T16:24:48.618 [25084.00059] controller-0 mtcAgent com nodeUtil.cpp ( 452) get_ip_addresses : Info : Floating IP : 192.168.204.2
2018-12-06T16:24:48.618 [25084.00060] controller-0 mtcAgent com nodeUtil.cpp ( 643) get_iface_macaddr : Info : Mac Address : 00:00:00:00:00:00
2018-12-06T16:24:48.618 [25084.00061] controller-0 mtcAgent --- nodeBase.cpp ( 681) log_adminAction : Info : controller-0 Add Action
2018-12-06T16:24:48.618 [25084.00062] controller-0 mtcAgent tok tokenUtil.cpp ( 707) tokenUtil_new_token : Info : controller-0 Requesting Authentication Token
2018-12-06T16:24:48.618 [25084.00063] controller-0 mtcAgent tok tokenUtil.cpp ( 118) tokenUtil_get_first : Info : controller-0 waiting on token request completion loop:0
mtcAgent: json_object.c:189: json_object_put: Assertion `jso->_ref_count > 0' failed.
./rebuild.sh: line 10: 25083 Aborted sudo ./maintenance/mtcAgent -fa

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/623149

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/623149
Committed: https://git.openstack.org/cgit/openstack/stx-metal/commit/?id=a92c543fd574e027f0de0bd17d8a67090364ef3d
Submitter: Zuul
Branch: master

commit a92c543fd574e027f0de0bd17d8a67090364ef3d
Author: Yan Chen <email address hidden>
Date: Fri Dec 7 00:47:21 2018 +0800

    No json_object_put() for the json_obj created by json_object_object_get_ex().

    It is stated in the json_object.h from version 0.11:
    https://github.com/json-c/json-c/blob/json-c-0.11/json_object.h#L271

    As on json-c 0.11, there's no assert to check for the ref_count, we wont get
      crashed. But on json-c 0.13.1 (latest release), json_object_put will check
      for the ref_count first, so mtcAgent will crash.

    Test Done:
    Run mtcAgent with json-c version 0.13.1 with this patch, no crash found.

    Closes-Bug: 1807097

    Change-Id: I7f954c97804ae01f831c94a36b9dbdbb34dbf083
    Signed-off-by: Yan Chen <email address hidden>

[Eric MacDonald (rocksolidmtce)]

The update this bug report was closed against has been reverted due to a compile error due to the declaration of an unused variable.

Please fix and retest.

[Ghada Khalil (gkhalil)]

Re-opening the launchpad as the original commit was reverted by:
https://review.openstack.org/#/c/623311/

A new fix will need to be submitted

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/623367

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/623367
Committed: https://git.openstack.org/cgit/openstack/stx-metal/commit/?id=1c38aff32a08cdd65080b8baa6d4fe02ee2083a4
Submitter: Zuul
Branch: master

commit 1c38aff32a08cdd65080b8baa6d4fe02ee2083a4
Author: Yan Chen <email address hidden>
Date: Fri Dec 7 19:20:16 2018 +0800

    No json_object_put() for the json_obj created by json_object_object_get_ex().

    It is stated in the json_object.h from version 0.11:
    https://github.com/json-c/json-c/blob/json-c-0.11/json_object.h#L271

    As on json-c 0.11, there's no assert to check for the ref_count, we wont get
      crashed. But on json-c 0.13.1 (latest release), json_object_put will check
      for the ref_count first, so mtcAgent will crash.

    Test Done:
    Run mtcAgent with json-c version 0.13.1 with this patch, no crash found.

    Closes-Bug: 1807097

    Change-Id: I35e5c1cad2e16ee0b6fc639380f1bdd3b64a7018
    Signed-off-by: Yan Chen <email address hidden>