Re: [PATCH net-next 3/3] net: dsa: mv88e6xxx: mac-auth/MAB implementation

[Vladimir Oltean]

On Tue, Mar 22, 2022 at 12:01:13PM +0100, Hans Schultz wrote:
> On fre, mar 18, 2022 at 15:19, Vladimir Oltean <olteanv@xxxxxxxxx> wrote:
> > On Fri, Mar 18, 2022 at 02:10:26PM +0100, Hans Schultz wrote:
> >> In the offloaded case there is no difference between static and dynamic
> >> flags, which I see as a general issue. (The resulting ATU entry is static
> >> in either case.)
> >
> > It _is_ a problem. We had the same problem with the is_local bit.
> > Independently of this series, you can add the dynamic bit to struct
> > switchdev_notifier_fdb_info and make drivers reject it.
> >
> >> These FDB entries are removed when link goes down (soft or hard). The
> >> zero DPV entries that the new code introduces age out after 5 minutes,
> >> while the locked flagged FDB entries are removed by link down (thus the
> >> FDB and the ATU are not in sync in this case).
> >
> > Ok, so don't let them disappear from hardware, refresh them from the
> > driver, since user space and the bridge driver expect that they are
> > still there.
> 
> I have now tested with two extra unmanaged switches (each connected to a
> seperate port on our managed switch, and when migrating from one port to
> another, there is member violations, but as the initial entry ages out,
> a new miss violation occurs and the new port adds the locked entry. In
> this case I only see one locked entry, either on the initial port or
> later on the port the host migrated to (via switch).
> 
> If I refresh the ATU entries indefinitly, then this migration will for
> sure not work, and with the member violation suppressed, it will be
> silent about it.

Manual says that migrations should trigger miss violations if configured
adequately, is this not the case?

> So I don't think it is a good idea to refresh the ATU entries
> indefinitely.
> 
> Another issue I see, is that there is a deadlock or similar issue when
> receiving violations and running 'bridge fdb show' (it seemed that
> member violations also caused this, but not sure yet...), as the unit
> freezes, not to return...

Have you enabled lockdep, debug atomic sleep, detect hung tasks, things
like that?