bonding: do not clear curr_active_slave prematurely when releasing all slaves

When releasing all slaves during bond destruction (all == true),
__bond_release_one() unconditionally clears bond->curr_active_slave to
NULL in every iteration.

If a backup slave is released before the active slave,
bond_alb_deinit_slave() triggers rlb_teach_disabled_mac_on_primary(),
which increments the active slave dev promiscuity counter and sets
bond_info->primary_is_promisc = 1.

Because bond->curr_active_slave was prematurely cleared to NULL when
releasing the backup slave, the subsequent iteration releasing the active
slave evaluates oldcurrent as NULL, so bond_change_active_slave(bond, NULL)
is skipped. Consequently, bond_alb_handle_active_change() is never called
to decrement the promiscuity counter, permanently leaking promiscuous
mode on the physical device after bond teardown.

When oldcurrent == slave, bond_change_active_slave(bond, NULL) already sets
bond->curr_active_slave to NULL. We only need to avoid selecting a new
active slave when all == true. Replace the if (all) branch with
if (!all && oldcurrent == slave).

Fixes: 0896341a44 ("bonding: fix bond_release_all inconsistencies")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jay Vosburgh <jv@jvosburgh.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260831203042.164466-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-08-31 20:30:42 +00:00 committed by Jakub Kicinski
parent 544d85de4d
commit af602c7aa5

View File

@ -2517,9 +2517,7 @@ static int __bond_release_one(struct net_device *bond_dev,
bond_alb_deinit_slave(bond, slave);
}
if (all) {
RCU_INIT_POINTER(bond->curr_active_slave, NULL);
} else if (oldcurrent == slave) {
if (!all && oldcurrent == slave) {
/* Note that we hold RTNL over this sequence, so there
* is no concern that another slave add/remove event
* will interfere.