[ovs-dev] [PATCH ovn v2 0/9] Incremental processing for flow installation.

Dumitru Ceara dceara at redhat.com
Mon Sep 14 16:45:41 UTC 2020


On 9/14/20 6:36 PM, Han Zhou wrote:
> 
> 
> On Mon, Sep 14, 2020 at 6:04 AM Dumitru Ceara <dceara at redhat.com
> <mailto:dceara at redhat.com>> wrote:
>>
>> On 9/11/20 9:16 PM, Dumitru Ceara wrote:
>> > On 9/11/20 8:39 PM, Han Zhou wrote:
>> >>
>> >>
>> >> On Fri, Sep 11, 2020 at 6:17 AM Dumitru Ceara <dceara at redhat.com
> <mailto:dceara at redhat.com>
>> >> <mailto:dceara at redhat.com <mailto:dceara at redhat.com>>> wrote:
>> >>>
>> >>> On 9/9/20 11:13 PM, Han Zhou wrote:
>> >>>> On Wed, Sep 9, 2020 at 6:39 AM Mark Michelson
> <mmichels at redhat.com <mailto:mmichels at redhat.com>
>> >> <mailto:mmichels at redhat.com <mailto:mmichels at redhat.com>>> wrote:
>> >>>>>
>> >>>>> Thanks for addressing my concerns on patch 9.
>> >>>>>
>> >>>>> Acked-by: Mark Michelson <mmichels at redhat.com
> <mailto:mmichels at redhat.com>
>> >> <mailto:mmichels at redhat.com <mailto:mmichels at redhat.com>>>
>> >>>>>
>> >>>>> Warning: I'm also ACKing Numan's patch series that also adds some
>> >>>>> lflow-level caching (but he is caching expressions). So whoever
> loses
>> >>>>> this merge race may have some work to do in order to apply their
> patch
>> >>>>> cleanly.
>> >>>>>
>> >>>> Thanks Mark for the review, and the warning :).
>> >>>> I applied the series to master, and also the first 4 patches to
>> >>>> branch-20.06 and patch 1,2,4 to branch-20.03, to fix the conjunction
>> >> flow
>> >>>> bug in those branches.
>> >>>>
>> >>>> Thanks,
>> >>>> Han
>> >>>>
>> >>>
>> >>> Hi Han,
>> >>>
>> >>> This seems to cause an assertion failure in ovn-controller
> compiled with
>> >>> today's OVS/OVN master branches. I'm not completely sure about the
> steps
>> >>> to reproduce because I was testing some other ovn-k8s related
> things but
>> >>> I did get a core dump and the NB/DB/conf DBs.
>> >>>
>> >>> I opened a RedHat BZ [0] (more for my tracking than anything else)
> and I
>> >>> shared there the OVS/OVN revisions and how to build the exact same
> image
>> >>> that I was running when I hit the crash.
>> >>>
>> >>> I'll try to investigate what's happening but you're probably more
>> >>> familiar with the code so any hints would be great.
>> >>>
>> >>> Thanks,
>> >>> Dumitru
>> >>>
>> >>> [0] https://bugzilla.redhat.com/show_bug.cgi?id=1878139
>> >>>
>> >>
>> >> Thanks Dumitru for reporting the issue. I reviewed the code and the
> test
>> >> cases again, and didn't figure out any problem yet. The failed
> assertion
>> >> "ovs_list_is_empty(&f->list_node) " is to assert that the desired_flow
>> >> is not accessed more than once in a single flood_remove call. This
>> >> should be true because the loop at
>> >>
> (https://github.com/ovn-org/ovn/blob/master/controller/ofctrl.c#L1126-L1134)
>> >> ensures that all flows in to_be_removed (which is the only list that
>> >> uses the "list_node" member) is detached from the cross reference
> lists,
>> >> so that in the following recursive calls these flows will never be
>> >> accessed again. Now that this assert fails, it could be some orphaned
>> >> pointer somewhere, leading to the "f" pointing to a flow that's already
>> >> destroyed.
>> >>
>> >> One thing not clear to me is the version you used for the testing.
> In BZ
>> >> you mentioned revision: 520189bf313054702f5f802acd7944cca3b6baaa.
>> >> However, in this revision, the line number of the assertion doesn't
>> >> match the one you pasted in BZ. What you pasted was 1135:
>> >
>> > The revision should be good, I think the problem is with the way I
>> > rebuilt the packages in the new container after I retrieved the core
> dump.
>> >
>> > The assert message clearly points to line 1108. This is from the old
>> > logs of the run where I saw the crash:
>> >
>> > 2020-09-11T11:53:18.426Z|00037|util|EMER|controller/ofctrl.c:1108:
>> > assertion ovs_list_is_empty(&f->list_node) failed in
>> > flood_remove_flows_for_sb_uuid()
>> >
>> >>
>> >> #6  0x00005607d73502fa in flood_remove_flows_for_sb_uuid
>> >> (flow_table=flow_table at entry=0x5607d8c4b380,
>> >> sb_uuid=sb_uuid at entry=0x5607d8f91430,
>> >> flood_remove_nodes=flood_remove_nodes at entry=0x7ffeccadb9c0) at
>> >> controller/ofctrl.c:1135
>> >>
>> >> What's in the code for revision (520189bf) is 1108:
>> >>
> https://github.com/ovn-org/ovn/blob/520189bf313054702f5f802acd7944cca3b6baaa/controller/ofctrl.c#L1108
>> >>
>> >> Did you change anything while doing the testing?
>> >>
>> >
>> > I'll try to replicate the issue again next week, maybe we get more info.
>> >
>> > Thanks,
>> > Dumitru
>> >
>>
>> Hi Han,
>>
>> I managed to minimize the way to replicate the crash (with OVN master).
>> I do:
>>
>> make sandbox
>> ovn-nbctl ls-add ls
>> ovn-nbctl lsp-add ls vm1
>> ovn-nbctl acl-add lsp-set-addresses vm1 "0a:58:fc:09:1d:4e
> fd00:10:244:1::5"
> 
> Thanks Dumitru! Here it seems a copy/paste problem. Could you provide
> the ACLs added?

There are no ACLs involved. This line was a mistake, please ignore it.
The conjunctions come from the IPv6 port security logical flows.

https://paste.centos.org/view/bb93f7d3

Regards,
Dumitru

> 
>> ovn-nbctl lsp-set-addresses vm1 "0a:58:fc:09:1d:4e fd00:10:244:1::5"
>> ovn-nbctl lsp-set-port-security vm1 "0a:58:fc:09:1d:4e fd00:10:244:1::5"
>> ovs-vsctl add-port br-int vm1 -- set interface vm1 type=internal -- set
>> interface vm1 external-ids:iface-id=vm1
>> sleep 1
>> ovs-vsctl set interface vm1 external-ids:iface-id=foo
>> sleep 1
>> ovs-vsctl set interface vm1 external-ids:iface-id=vm1
>> sleep 1
>> ovs-vsctl set interface vm1 external-ids:iface-id=foo
>>
>> This crashes ovn-controller and if I look at the openflows before the
>> last port unbind, I notice some weird flows with action:
>>
>>
> actions=conjunction(2,2/2),conjunction(2,2/2),conjunction(2,2/2),conjunction(2,2/2),conjunction(2,2/2),conjunction(2,2/2),conjunction(2,2/2)
>>
>> This looks broken. I tried to figure out what's happening but
>> unfortunately I didn't manage to.
>>
>> Hope this helps pinpoint the root cause.
>>
>> Regards,
>> Dumitru
>>



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