[ovs-discuss] OVN /OVS openvswitch: ovs-system: deferred action limit reached, drop recirc action

Krzysztof Klimonda kklimonda at syntaxhighlighted.com
Wed Aug 4 08:16:56 UTC 2021


Hi Ammad,

(Re-adding ovs-discuss at openvswitch.org to CC to keep track of the discussion)

Thanks for testing it with SNAT enabled/disabled and verifying that it seems to be related.

As for the impact of this bug I have to say I'm unsure. I have theorized that this could the cause for (or at least connected to) BFD sessions being dropped between gateway chassises, but I couldn't really validate it.

My linked patch is pretty old and no longer applies cleanly on master, but I'd be interested in getting some feedback from developers on whether I'm even fixing the right thing.

Regards,
Krzysztof

On Wed, Aug 4, 2021, at 09:02, Ammad Syed wrote:
> I am able to reproduce this issue with snat enabled network and 
> accessing the snat IP from external network can reproduce this issue . 
> If I keep snat disable, then I didn't see these logs in syslog.
> 
> Ammad
> 
> On Tue, Aug 3, 2021 at 6:39 PM Ammad Syed <syedammad83 at gmail.com> wrote:
> > Thanks. Let me try to reproduce it with this way.
> > 
> > Can you please advise if this will cause any trouble if we have this bug in production? Any workaround to avoid this issue?
> > 
> > Ammad
> > 
> > On Tue, Aug 3, 2021 at 5:56 PM Krzysztof Klimonda <kklimonda at syntaxhighlighted.com> wrote:
> >> Hi,
> >> 
> >> To reproduce it (on openstack. although the issue does not seem to be openstack-specific) I've created a network with SNAT enabled (which is default) and set its external gateway to my external network. Next, I've tried establishing TCP session from the outside to IP address assigned to the router and checked dmesg on the chassis that the port is assigned to for "ovs-system: deferred action limit reached, drop recirc action" messages.
> >> 
> >> Best Regards,
> >> Krzysztof
> >> 
> >> On Tue, Aug 3, 2021, at 09:05, Ammad Syed wrote:
> >> > Hi Krzysztof,
> >> > 
> >> > Yes I might be stuck in this issue. How can I check if there is any 
> >> > loop in lflow-list ?
> >> > 
> >> > Ammad
> >> > 
> >> > On Tue, Aug 3, 2021 at 2:14 AM Krzysztof Klimonda 
> >> > <kklimonda at syntaxhighlighted.com> wrote:
> >> > > Hi,
> >> > > 
> >> > > Not sure if it's related, but I've seen this bug in ovn 20.12 release, where routing loop was related to flows created to handle SNAT, I've sent an RFC patch few months back but didn't really have time to follow up on it since then to get some feedback: https://www.mail-archive.com/ovs-dev@openvswitch.org/msg53195.html
> >> > > I was planning on re-testing it with 21.06 release and follow up on the patch.
> >> > > 
> >> > > On Mon, Aug 2, 2021, at 21:31, Han Zhou wrote:
> >> > > > 
> >> > > > 
> >> > > > On Mon, Aug 2, 2021 at 5:07 AM Ammad Syed <syedammad83 at gmail.com> wrote:
> >> > > > >
> >> > > > > Hello, 
> >> > > > >
> >> > > > > I am using openstack with OVN 20.12 and OVS 2.15.0 on ubuntu 20.04. I am using geneve tenant network and vlan provider network. 
> >> > > > >
> >> > > > > I am continuously getting below messages in my dmesg logs continuously on compute node 1 only the other two compute nodes have no such messages. 
> >> > > > >
> >> > > > > [275612.826698] openvswitch: ovs-system: deferred action limit reached, drop recirc action
> >> > > > > [275683.750343] openvswitch: ovs-system: deferred action limit reached, drop recirc action
> >> > > > > [276102.200772] openvswitch: ovs-system: deferred action limit reached, drop recirc action
> >> > > > > [276161.575494] openvswitch: ovs-system: deferred action limit reached, drop recirc action
> >> > > > > [276210.262524] openvswitch: ovs-system: deferred action limit reached, drop recirc action
> >> > > > >
> >> > > > > I have tried by reinstalling (OS everything) compute node 1 but still having same errors.
> >> > > > >
> >> > > > > Need your advise.
> >> > > > >
> >> > > > > --
> >> > > > > Regards,
> >> > > > >
> >> > > > >
> >> > > > > Syed Ammad Ali
> >> > > > > _______________________________________________
> >> > > > > discuss mailing list
> >> > > > > discuss at openvswitch.org
> >> > > > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> >> > > > 
> >> > > > Hi Syed,
> >> > > > 
> >> > > > Could you check if you have routing loops (i.e. a packet being routed 
> >> > > > back and forth between logical routers infinitely) in your logical 
> >> > > > topology?
> >> > > > 
> >> > > > Thanks,
> >> > > > Han
> >> > > > _______________________________________________
> >> > > > discuss mailing list
> >> > > > discuss at openvswitch.org
> >> > > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> >> > > > 
> >> > > 
> >> > > 
> >> > > -- 
> >> > >   Krzysztof Klimonda
> >> > >   kklimonda at syntaxhighlighted.com
> >> > > _______________________________________________
> >> > > discuss mailing list
> >> > > discuss at openvswitch.org
> >> > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> >> > 
> >> > 
> >> > -- 
> >> > Regards,
> >> > 
> >> > 
> >> > Syed Ammad Ali
> >> 
> >> 
> >> -- 
> >>   Krzysztof Klimonda
> >>   kklimonda at syntaxhighlighted.com
> > -- 
> > Regards,
> > 
> > 
> > Syed Ammad Ali
> 
> 
> -- 
> Regards,
> 
> 
> Syed Ammad Ali


-- 
  Krzysztof Klimonda
  kklimonda at syntaxhighlighted.com


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