4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jonas Gorski <jonas.gorski@xxxxxxxx>
[ 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>
---
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 d898e3814f91..a6e4901909e3 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -1116,12 +1116,10 @@ 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;
}
--
2.43.0
