Comment 36 for bug 1697243

I've had a look at Margin's last trace.

(only the lines related to cookies and stale flow deletion, edited for readability)

2017-07-15 21:13:27.052 6 INFO neutron.common.config [-] /usr/bin/neutron-openvswitch-agent version 10.0.1
2017-07-15 21:13:33.118 6 DEBUG ....openflow.native.ofswitch [ - - - - -] Reserved cookies for br-int: set([10385564020546830277L])
2017-07-15 21:13:33.120 6 DEBUG ....openflow.native.ofswitch [ - - - - -] Reserved cookies for provision: set([10900502818113047970L])
2017-07-15 21:13:33.124 6 DEBUG ....openflow.native.ofswitch [ - - - - -] Reserved cookies for br-ex2: set([9707595023152995281L])

2017-07-15 21:13:33.125 6 WARNING ....openflow.native.ofswitch [ - - - - -] Deleting flow with cookie 0x0
2017-07-15 21:13:33.128 6 WARNING ....openflow.native.ofswitch [ - - - - -] Deleting flow with cookie 0xbdc758dfcf1b2f4d
                                                                                                      ^^^^^^^^^^^^^^^^^^

2017-07-15 21:13:33.133 6 DEBUG ....openflow.native.ofswitch [ - - - - -] Reserved cookies for br-ex: set([13674996511809417037L])
                                                                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

So 0xbdc758dfcf1b2f4d is one of the reserved cookies of br-ex, but was also found when listing flows on br-ex2. A flow was created on a bridge (be-ex2) with a cookie that is a registered cookie on another bridge (br-ex). This, of course, is not supposed to happen.

I haven't yet looked further what could be the root cause.