panic in an ovnkube-master pod

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x68 pc=0x193c7ee]

goroutine 1 [running]:
github.com/ovn-org/ovn-kubernetes/go-controller/pkg/network-controller-manager.(*netAttachDefinitionController).GetAllNetworkControllers(0x0)
	/go/src/github.com/openshift/ovn-kubernetes/go-controller/pkg/network-controller-manager/network_attach_def_controller.go:307 +0x2e
github.com/ovn-org/ovn-kubernetes/go-controller/pkg/network-controller-manager.(*networkControllerManager).Stop(0xc00068e000)
	/go/src/github.com/openshift/ovn-kubernetes/go-controller/pkg/network-controller-manager/network_controller_manager.go:421 +0x5c
main.runOvnKube(0xc0000b2d80, 0xc0000b2d80?)
	/go/src/github.com/openshift/ovn-kubernetes/go-controller/cmd/ovnkube/ovnkube.go:314 +0xbc5
main.main.func1(0xc0002fe800?)
	/go/src/github.com/openshift/ovn-kubernetes/go-controller/cmd/ovnkube/ovnkube.go:108 +0x1d
github.com/urfave/cli/v2.(*App).RunContext(0xc0000d8d80, \{0x2148e48?, 0xc00042b600}, \{0xc000006a00, 0x27, 0x28})
	/go/src/github.com/openshift/ovn-kubernetes/go-controller/vendor/github.com/urfave/cli/v2/app.go:315 +0x9f5
main.main()
	/go/src/github.com/openshift/ovn-kubernetes/go-controller/cmd/ovnkube/ovnkube.go:132 +0xba9 * [pod logs|https://gcsweb-ci.apps.ci.l2s4.p1.openshiftapps.com/gcs/origin-ci-test/pr-logs/pull/27694/pull-ci-openshift-origin-master-e2e-aws-ovn-serial/1620801400306929664/artifacts/e2e-aws-ovn-serial/gather-extra/artifacts/pods/openshift-ovn-kubernetes_ovnkube-master-4qn9x_ovnkube-master_previous.log]