This is a note to let you know that I've just added the patch titled net: bridge: sync fdb to new unicast-filtering ports to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-bridge-sync-fdb-to-new-unicast-filtering-ports.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a019abd8022061b917da767cd1a66ed823724eab Mon Sep 17 00:00:00 2001 From: Wolfgang Bumiller <w.bumiller@xxxxxxxxxxx> Date: Fri, 2 Jul 2021 14:07:36 +0200 Subject: net: bridge: sync fdb to new unicast-filtering ports From: Wolfgang Bumiller <w.bumiller@xxxxxxxxxxx> commit a019abd8022061b917da767cd1a66ed823724eab upstream. Since commit 2796d0c648c9 ("bridge: Automatically manage port promiscuous mode.") bridges with `vlan_filtering 1` and only 1 auto-port don't set IFF_PROMISC for unicast-filtering-capable ports. Normally on port changes `br_manage_promisc` is called to update the promisc flags and unicast filters if necessary, but it cannot distinguish between *new* ports and ones losing their promisc flag, and new ports end up not receiving the MAC address list. Fix this by calling `br_fdb_sync_static` in `br_add_if` after the port promisc flags are updated and the unicast filter was supposed to have been filled. Fixes: 2796d0c648c9 ("bridge: Automatically manage port promiscuous mode.") Signed-off-by: Wolfgang Bumiller <w.bumiller@xxxxxxxxxxx> Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/bridge/br_if.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -486,7 +486,7 @@ int br_add_if(struct net_bridge *br, str struct net_bridge_port *p; int err = 0; unsigned br_hr, dev_hr; - bool changed_addr; + bool changed_addr, fdb_synced = false; /* Don't allow bridging non-ethernet like devices, or DSA-enabled * master network devices since the bridge layer rx_handler prevents @@ -556,6 +556,19 @@ int br_add_if(struct net_bridge *br, str list_add_rcu(&p->list, &br->port_list); nbp_update_port_count(br); + if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) { + /* When updating the port count we also update all ports' + * promiscuous mode. + * A port leaving promiscuous mode normally gets the bridge's + * fdb synced to the unicast filter (if supported), however, + * `br_port_clear_promisc` does not distinguish between + * non-promiscuous ports and *new* ports, so we need to + * sync explicitly here. + */ + fdb_synced = br_fdb_sync_static(br, p) == 0; + if (!fdb_synced) + netdev_err(dev, "failed to sync bridge static fdb addresses to this port\n"); + } netdev_update_features(br->dev); @@ -596,6 +609,8 @@ int br_add_if(struct net_bridge *br, str return 0; err7: + if (fdb_synced) + br_fdb_unsync_static(br, p); list_del_rcu(&p->list); br_fdb_delete_by_port(br, p, 0, 1); nbp_update_port_count(br); Patches currently in stable-queue which might be from w.bumiller@xxxxxxxxxxx are queue-4.9/net-bridge-sync-fdb-to-new-unicast-filtering-ports.patch