linux-kernel - Re: [PATCH RFC net-next 0/3] net: vlan: fix bridge binding behavior and add selftests

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Date:   Wed, 10 Aug 2022 11:00:24 -0400
From:   Sevinj Aghayeva <sevinj.aghayeva@...il.com>
To:     Nikolay Aleksandrov <razor@...ckwall.org>
Cc:     netdev@...r.kernel.org, aroulin@...dia.com, sbrivio@...hat.com,
        roopa@...dia.com, "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org,
        bridge@...ts.linux-foundation.org
Subject: Re: [PATCH RFC net-next 0/3] net: vlan: fix bridge binding behavior
 and add selftests

On Wed, Aug 10, 2022 at 10:50 AM Nikolay Aleksandrov
<razor@...ckwall.org> wrote:
>
> On 10/08/2022 17:42, Sevinj Aghayeva wrote:
> >
> >
> > On Wed, Aug 10, 2022 at 4:54 AM Nikolay Aleksandrov <razor@...ckwall.org <mailto:razor@...ckwall.org>> wrote:
> >
> >     On 10/08/2022 06:11, Sevinj Aghayeva wrote:
> >     > When bridge binding is enabled for a vlan interface, it is expected
> >     > that the link state of the vlan interface will track the subset of the
> >     > ports that are also members of the corresponding vlan, rather than
> >     > that of all ports.
> >     >
> >     > Currently, this feature works as expected when a vlan interface is
> >     > created with bridge binding enabled:
> >     >
> >     >   ip link add link br name vlan10 type vlan id 10 protocol 802.1q \
> >     >         bridge_binding on
> >     >
> >     > However, the feature does not work when a vlan interface is created
> >     > with bridge binding disabled, and then enabled later:
> >     >
> >     >   ip link add link br name vlan10 type vlan id 10 protocol 802.1q \
> >     >         bridge_binding off
> >     >   ip link set vlan10 type vlan bridge_binding on
> >     >
> >     > After these two commands, the link state of the vlan interface
> >     > continues to track that of all ports, which is inconsistent and
> >     > confusing to users. This series fixes this bug and introduces two
> >     > tests for the valid behavior.
> >     >
> >     > Sevinj Aghayeva (3):
> >     >   net: core: export call_netdevice_notifiers_info
> >     >   net: 8021q: fix bridge binding behavior for vlan interfaces
> >     >   selftests: net: tests for bridge binding behavior
> >     >
> >     >  include/linux/netdevice.h                     |   2 +
> >     >  net/8021q/vlan.h                              |   2 +-
> >     >  net/8021q/vlan_dev.c                          |  25 ++-
> >     >  net/core/dev.c                                |   7 +-
> >     >  tools/testing/selftests/net/Makefile          |   1 +
> >     >  .../selftests/net/bridge_vlan_binding_test.sh | 143 ++++++++++++++++++
> >     >  6 files changed, 172 insertions(+), 8 deletions(-)
> >     >  create mode 100755 tools/testing/selftests/net/bridge_vlan_binding_test.sh
> >     >
> >
> >     Hi,
> >     NETDEV_CHANGE event is already propagated when the vlan changes flags,
> >
> >
> > I'm not sure if NETDEV_CHANGE is actually propagated when the vlan changes flags. The two functions in the bridge module that handle NETDEV_CHANGE are br_vlan_port_event  and br_vlan_bridge_event. I've installed probes for both, and when I'm changing flags using "sudo ip link set vlan10 type vlan bridge_binding on", I don't see any of those functions getting called, although I do see vlan_dev_change_flags getting called. I think there may be a bug in core/dev.c:__dev_notify_flags.
>
> are both vlan and bridge interfaces up?
> what exactly are you probing for?


I first run the attached pre.sh script that sets up the environment
and creates a vlan interface with bridge binding off. I then start
recording with perf, and here's the list of probes:

$ sudo ./k/linux/tools/perf/perf probe -l
  probe:br_vlan_bridge_event (on br_vlan_bridge_event in bridge with event dev)
  probe:br_vlan_port_event (on br_vlan_port_event in bridge with event)
  probe:br_vlan_set_vlan_dev_state (on br_vlan_set_vlan_dev_state in
bridge with br vlan_dev)
  probe:register_vlan_dev (on register_vlan_dev in 8021q with dev)
  probe:vlan_changelink (on vlan_changelink in 8021q with dev)
  probe:vlan_dev_change_flags (on vlan_dev_change_flags in 8021q with dev)
  probe:vlan_dev_fix_features (on vlan_dev_fix_features in 8021q with dev)
  probe:vlan_dev_init  (on vlan_dev_init in 8021q with dev)
  probe:vlan_dev_ioctl (on vlan_dev_ioctl in 8021q with dev)
  probe:vlan_dev_open  (on vlan_dev_open in 8021q with dev)
  probe:vlan_dev_stop  (on vlan_dev_stop in 8021q with dev)
  probe:vlan_dev_uninit (on vlan_dev_uninit in 8021q with dev)
  probe:vlan_newlink   (on vlan_newlink in 8021q with dev)

I then run the following command to turn the bridge binding flag on:

$ sudo ip link set vlan10 type vlan bridge_binding on

Then I stop the recording and print out the events, and I see this. I
don't see br_vlan_port_event or br_vlan_bridge_event getting called.

              ip  5933 [003]  2204.722470:
probe:vlan_changelink: (ffffffffc1042b50) dev="vlan10"
              ip  5933 [003]  2204.722476:
probe:vlan_dev_change_flags: (ffffffffc1042600) dev="vlan10"

Am I doing something wrong?

Thanks



>
>
> I can see the NETDEV_CHANGE event go through when changing the loose binding.
>
>
>
>


-- 

Sevinj.Aghayeva

Download attachment "pre.sh" of type "application/x-sh" (1128 bytes)