Comment 3 for bug 1811515

I think that issue which I mentioned is reason of failed tests when it happens during adding new interface to router, like in this example http://logs.openstack.org/43/628943/2/check/tempest-full/07fe3fe/controller/logs/screen-q-l3.txt.gz?level=ERROR#_Jan_13_17_57_18_302877 or something similar.
If it happens during e.g. removing router or listing devices it not cause failures.

That's why IMO it not happens always.

What I also found is that always just before such error, there is error "forced shutdown procedure, clean up netns manually" which comes from pyroute2: https://github.com/svinota/pyroute2/blob/ad992d14f47d82b39b9de3801210b51386fe42eb/pyroute2/netns/nslink.py#L199 and I suspect that maybe when one call is closing namespace and it fails, pyroute2 is doing something wrong and closes also other file descriptors which cause issue in other worker which wants to do something in namespace.