Thanks Ben. I have written a test and can confirm that latest OVS has a vswitchd crash in this case. After a long chain of calls starting with handle_packet_out calling ofproto_packet_out_finish, and ending with dp_netdev_run_meter, dp_packet_delete is called to dispose of the message. Then handle_packet_out calls ofproto_packet_out_uninit which calls dp_packet_delete to delete the same message.
I am a bit stumped as to how to fix this. Stopping the meter code from deleting the packet would not work for other cases which don't seem to crash, stopping the packet_out code from deleting the packet would not work for when the meter is not invoked. Creating a copy of the packet wouldn't work because it would then have to be disposed of in the normal, non-meter case. Adding special flags would be a major change, as would reference counting on the packet buffer. About the best I can think of is a flag to cover this specific case, maybe added to the packet metadata, which would need to be initialised false, and then be set true by the packet_out code. Maybe call it "meter_do_not_delete"? I can try this to see if it works but wonder if packet_metadata can be altered just like that. Or if there are better ways of doing this. Tony ________________________________________ From: Ben Pfaff <b...@ovn.org> Sent: Saturday, 29 May 2021 5:27 a.m. To: Tony van der Peet Cc: b...@openvswitch.org Subject: Re: [ovs-discuss] Where does complex packet_out/meters behaviour test belong? On Fri, May 28, 2021 at 05:00:46AM +0000, Tony van der Peet wrote: > I want to add a unit test that checks what happens when a packet_out message > with output port OFPP_TABLE is dropped due to the action of a meter (our > version of vswitchd crashes when I run this test with our oftest framework). > > > Where do you suggest I put this test? There are a few packet-out tests in http://scanmail.trustwave.com/?c=20988&d=iKix4E8S7LYunNE_BL4IXm1Ak3fMb7yMJ8K3pmQBJw&u=http%3a%2f%2fofproto-dpif%2eat perhaps just after this cluster: ofproto-dpif.at:AT_SETUP([ofproto-dpif packet-out controller]) ofproto-dpif.at:AT_SETUP([ofproto-dpif packet-out controller (patch port)]) ofproto-dpif.at:AT_SETUP([ofproto-dpif packet-out pipeline match field (OpenFlow 1.5)]) ofproto-dpif.at:AT_SETUP([ofproto-dpif packet-out goto_table]) ofproto-dpif.at:AT_SETUP([ofproto-dpif packet-out table-miss (continue)]) _______________________________________________ discuss mailing list disc...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
