This bugzilla is opened in order to make include the following upstream fix in downstream OVS 2.6.
Description (from github):
The ports which are attached mrouters or hosts, were destroyed
by users via ovs-vsctl commands. Currently the vswitch will
segfault if users use "ovs-appctl mdb/show" to show mdb info.
This patch avoids a segfault.
[1] https://github.com/openvswitch/ovs/commit/0ae08f8334f9d62889031277722eccac33b404ef