Re: [PATCH net v2 2/2] selftests: openvswitch: add tests for tunnel vport refcounting

[Ilya Maximets <i.maximets@ovn.org>]

On 5/5/26 3:25 PM, Paolo Abeni wrote:
> On 5/1/26 1:38 AM, Ilya Maximets wrote:
>> @@ -830,6 +831,42 @@ test_tunnel_metadata() {
>>  	return 0
>>  }
>>  
>> +test_tunnel_refcount() {
>> +	sbxname="test_tunnel_refcount"
>> +	sbx_add "${sbxname}" || return 1
>> +
>> +	ovs_sbx "${sbxname}" ip netns add trefns || return 1
>> +	on_exit "ovs_sbx ${sbxname} ip netns del trefns"
>> +
>> +	for tun_type in gre vxlan geneve; do
>> +		info "testing ${tun_type} tunnel vport refcount"
>> +
>> +		ovs_sbx "${sbxname}" ip netns exec trefns \
>> +			python3 $ovs_base/ovs-dpctl.py \
>> +			add-dp dp-${tun_type} || return 1
>> +
>> +		ovs_sbx "${sbxname}" ip netns exec trefns \
>> +			python3 $ovs_base/ovs-dpctl.py \
>> +			add-if --no-lwt -t ${tun_type} \
>> +			dp-${tun_type} ovs-${tun_type}0 || return 1
>> +
>> +		ovs_wait ip -netns trefns link show \
>> +			ovs-${tun_type}0 >/dev/null 2>&1 || return 1
>> +
>> +		info "deleting dp - may hang if reference counting is broken"
>> +		ovs_sbx "${sbxname}" ip netns exec trefns \
>> +			python3 $ovs_base/ovs-dpctl.py \
>> +			del-dp dp-${tun_type} &
>> +
>> +		dev_removed() {
>> +			! ip -netns trefns link show "$1" >/dev/null 2>&1
>> +		}
>> +		ovs_wait dev_removed dp-${tun_type} || return 1
>> +		ovs_wait dev_removed ovs-${tun_type}0 || return 1
> 
> FTR, here sashiko laments that if the reference counting is broken and
> the del-dp process hangs, this could leave the background del-dp python
> process running indefinitely.
> 
> I guess that if reference counting is broken inside the kernel, very
> likely an host/VM reboot is needed, and the above does not matter.

Yes, I have a note about that in the cover letter.