commit 9049b647b78458529c403985d4c00e4a1df53371
Author: Lucian Petrut <lpetrut@cloudbasesolutions.com>
Date:   Tue Apr 14 11:25:18 2020 +0300

    windows: fix terminating processes
    
    The neutron Windows exec call helper doesn't properly handle the
    situation in which the process that it's trying to kill was already
    terminated, in which case using wmi to fetch the process can raise
    an exception.
    
    This change ensures that those WMI exceptions will be properly
    handled.
    
    Closes-Bug: 1872663
    
    Change-Id: I00c810fe541ac5e1e9923155fe90eb07a0b4b3dd
    (cherry picked from commit 8fd3e884c7953645862663400af181ba233ec28f)

diff --git a/neutron/agent/windows/utils.py b/neutron/agent/windows/utils.py
index f97d3e4..515a122 100644
--- a/neutron/agent/windows/utils.py
+++ b/neutron/agent/windows/utils.py
@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import ctypes
 import io
 import os
 
@@ -38,6 +39,8 @@ LOG = logging.getLogger(__name__)
 subprocess = eventlet.patcher.original('subprocess')
 subprocess.threading = eventlet.patcher.original('threading')
 
+ERROR_KEY_DELETED = 0x03FA
+
 
 def create_process(cmd, run_as_root=False, addl_env=None,
                    tpool_proxy=True):
@@ -71,8 +74,16 @@ def _get_wmi_process(pid):
     if not pid:
         return None
 
-    conn = wmi.WMI()
-    processes = conn.Win32_Process(ProcessId=pid)
+    try:
+        conn = wmi.WMI()
+        processes = conn.Win32_Process(ProcessId=pid)
+    except wmi.x_wmi as exc:
+        hresult = exc.com_error.hresult
+        err_code = ctypes.c_uint(hresult).value & 0xFFFF
+        if err_code == ERROR_KEY_DELETED:
+            return None
+        raise
+
     if processes:
         return processes[0]
     return None
diff --git a/neutron/tests/unit/agent/windows/test_utils.py b/neutron/tests/unit/agent/windows/test_utils.py
index 229f6fe..6c291e7 100644
--- a/neutron/tests/unit/agent/windows/test_utils.py
+++ b/neutron/tests/unit/agent/windows/test_utils.py
@@ -26,6 +26,13 @@ from neutron.agent.windows import utils
 from neutron.tests import base
 
 
+class x_wmi(Exception):
+    def __init__(self, info='', com_error=None):
+        super(x_wmi, self).__init__(info)
+        self.info = info
+        self.com_error = com_error
+
+
 @ddt.ddt
 class WindowsUtilsTestCase(base.BaseTestCase):
     @mock.patch('os.environ', {mock.sentinel.key0: mock.sentinel.val0})
@@ -87,6 +94,25 @@ class WindowsUtilsTestCase(base.BaseTestCase):
         if pid:
             mock_conn.Win32_Process.assert_called_once_with(ProcessId=pid)
 
+    @ddt.data({},
+              {"hresult": 0xff,
+               "expect_exc": True})
+    @ddt.unpack
+    @mock.patch.object(utils, 'wmi', create=True)
+    def test_get_wmi_process_exc(self, mock_wmi, expect_exc=False,
+                                 hresult=0x800703FA):
+        mock_conn = mock_wmi.WMI.return_value
+        mock_wmi.x_wmi = x_wmi
+        com_error = mock.Mock(hresult=hresult)
+        exc = x_wmi(com_error=com_error)
+        mock_conn.Win32_Process.side_effect = exc
+
+        if expect_exc:
+            self.assertRaises(
+                x_wmi, utils._get_wmi_process, mock.sentinel.pid)
+        else:
+            self.assertIsNone(utils._get_wmi_process(mock.sentinel.pid))
+
     @ddt.data(True, False)
     @mock.patch.object(utils, '_get_wmi_process')
     def test_kill_process(self, process_exists, mock_get_process):