This is a note to let you know that I've just added the patch titled net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN to the 5.10-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-br_fdb_external_learn_add-always-set-ext_.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6ae272a3aa70ebbb052eaa9683fe6a08b7467e84 Author: Jonas Gorski <jonas.gorski@xxxxxxxx> Date: Tue Sep 3 10:19:57 2024 +0200 net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN [ Upstream commit bee2ef946d3184e99077be526567d791c473036f ] When userspace wants to take over a fdb entry by setting it as EXTERN_LEARNED, we set both flags BR_FDB_ADDED_BY_EXT_LEARN and BR_FDB_ADDED_BY_USER in br_fdb_external_learn_add(). If the bridge updates the entry later because its port changed, we clear the BR_FDB_ADDED_BY_EXT_LEARN flag, but leave the BR_FDB_ADDED_BY_USER flag set. If userspace then wants to take over the entry again, br_fdb_external_learn_add() sees that BR_FDB_ADDED_BY_USER and skips setting the BR_FDB_ADDED_BY_EXT_LEARN flags, thus silently ignores the update. Fix this by always allowing to set BR_FDB_ADDED_BY_EXT_LEARN regardless if this was a user fdb entry or not. Fixes: 710ae7287737 ("net: bridge: Mark FDB entries that were added by user as such") Signed-off-by: Jonas Gorski <jonas.gorski@xxxxxxxx> Acked-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx> Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx> Link: https://patch.msgid.link/20240903081958.29951-1-jonas.gorski@xxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 8a6470a21702..8751571a3cb0 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -1238,12 +1238,10 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p, modified = true; } - if (test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags)) { + if (test_and_set_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags)) { /* Refresh entry */ fdb->used = jiffies; - } else if (!test_bit(BR_FDB_ADDED_BY_USER, &fdb->flags)) { - /* Take over SW learned entry */ - set_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags); + } else { modified = true; }