5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jonas Gorski jonas.gorski@bisdn.de
[ 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@bisdn.de Acked-by: Nikolay Aleksandrov razor@blackwall.org Reviewed-by: Ido Schimmel idosch@nvidia.com Link: https://patch.msgid.link/20240903081958.29951-1-jonas.gorski@bisdn.de Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/bridge/br_fdb.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 83d6be3f87f1..89e0a6808d30 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -1138,12 +1138,10 @@ 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; }