Re: net: bridge: propagate error code and extack from br_mc_disabled_update

[Vladimir Oltean <olteanv@gmail.com>]

On Wed, Apr 21, 2021 at 11:37:25AM -0700, Florian Fainelli wrote:
> On 4/21/2021 11:35 AM, Christian Borntraeger wrote:
> > On 21.04.21 20:18, Christian Borntraeger wrote:
> >> Whatever version landed in next, according to bisect this broke
> >> libvirt/kvms use of bridges:
> >>
> >>
> >> # virsh start s31128001
> >> error: Failed to start domain 's31128001'
> >> error: Unable to add bridge virbr1 port vnet0: Operation not supported
> >>
> >> # grep vnet0 /var/log/libvirt/libvirtd.log
> >>
> >> 2021-04-21 07:43:09.453+0000: 2460: info : virNetDevTapCreate:240 :
> >> created device: 'vnet0'
> >> 2021-04-21 07:43:09.453+0000: 2460: debug :
> >> virNetDevSetMACInternal:287 : SIOCSIFHWADDR vnet0
> >> MAC=fe:bb:83:28:01:02 - Success
> >> 2021-04-21 07:43:09.453+0000: 2460: error : virNetDevBridgeAddPort:633
> >> : Unable to add bridge virbr1 port vnet0: Operation not supported
> >> 2021-04-21 07:43:09.466+0000: 2543: debug : udevHandleOneDevice:1695 :
> >> udev action: 'add': /sys/devices/virtual/net/vnet0
> >>
> >> Christian
> >>
> > 
> > For reference:
> > 
> > ae1ea84b33dab45c7b6c1754231ebda5959b504c is the first bad commit
> > commit ae1ea84b33dab45c7b6c1754231ebda5959b504c
> > Author: Florian Fainelli <f.fainelli@gmail.com>
> > Date:   Wed Apr 14 22:22:57 2021 +0300
> > 
> >    net: bridge: propagate error code and extack from br_mc_disabled_update
> >       Some Ethernet switches might only be able to support disabling
> > multicast
> >    snooping globally, which is an issue for example when several bridges
> >    span the same physical device and request contradictory settings.
> >       Propagate the return value of br_mc_disabled_update() such that this
> >    limitation is transmitted correctly to user-space.
> >       Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> >    Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> >    Signed-off-by: David S. Miller <davem@davemloft.net>
> > 
> > net/bridge/br_multicast.c | 28 +++++++++++++++++++++-------
> > net/bridge/br_netlink.c   |  4 +++-
> > net/bridge/br_private.h   |  3 ++-
> > net/bridge/br_sysfs_br.c  |  8 +-------
> > 4 files changed, 27 insertions(+), 16 deletions(-)
> > 
> > not sure if it matters this is on s390.
> > A simple reproducer is virt-install, e.g.
> > virt-install --name test --disk size=12 --memory=2048 --vcpus=2
> > --location
> > http://ports.ubuntu.com/ubuntu-ports/dists/bionic/main/installer-s390x/
> 
> Thanks, I will kick off a reproducer and let you know.
> -- 
> Florian

Hey, you guys are moving fast, faster than it took me to open my email client...

Sorry for the breakage, Christian, I've just sent a patch with what I
think is wrong, could you give it a try?

Thanks!