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FAILED: patch "[PATCH] net: bridge: sync fdb to new unicast-filtering ports" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Jul 22, 2021

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The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a019abd8022061b917da767cd1a66ed823724eab Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <[email protected]>
Date: Fri, 2 Jul 2021 14:07:36 +0200
Subject: [PATCH] net: bridge: sync fdb to new unicast-filtering ports

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 <[email protected]>
Acked-by Nikolay Aleksandrov <[email protected]>
Signed-off-by David S. Miller <[email protected]>
net/bridge/br_if.c +16 -1
index f7d2f472ae24..6e4a32354a13 100644
@@ -562,7 +562,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
 	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. */
 	if ((dev->flags & IFF_LOOPBACK) ||

@@ -652,6 +652,19 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
 	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);
 

@@ -701,6 +714,8 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
 	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);