net: team: don't recurse on the port's netdev ops lock

__team_port_change_send() calls __ethtool_get_link_ksettings() on
the port, which will soon take the port's ops lock. The notifier
caller already holds it while the slave-add/del callers do not,
so the function would either deadlock or run unprotected depending
on the path.

Make __team_port_change_send() expect the port's ops lock held and
switch to netif_get_link_ksettings(). team_device_event()'s NETDEV_UP /
NETDEV_CHANGE already arrive with the port's ops lock held.
team_port_add() now take it explicitly.

Note that NETDEV_DOWN and team_port_del() will pass false as @linkup
so they will not execute netif_get_link_ksettings(). This is fortunate
as NETDEV_DOWN has somewhat mixed locking right now.

Link: https://patch.msgid.link/20260603012840.2254293-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index f51388d50307fdcc9ba530f1a8325ae287cf90dd..feaa75fbf8fc2551665d3915f8145b50344f70ba 100644 (file)
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -1375,7 +1375,9 @@ static int team_port_add(struct team *team, struct net_device *port_dev,
        list_add_tail_rcu(&port->list, &team->port_list);
        team_port_enable(team, port);
        netdev_compute_master_upper_features(dev, true);
+       netdev_lock_ops(port_dev);
        __team_port_change_port_added(port, !!netif_oper_up(port_dev));
+       netdev_unlock_ops(port_dev);
        __team_options_change_check(team);
 
        netdev_info(dev, "Port device %s added\n", portname);
@@ -3090,7 +3092,7 @@ static void __team_port_change_send(struct team_port *port, bool linkup)
        if (linkup) {
                struct ethtool_link_ksettings ecmd;
 
-               err = __ethtool_get_link_ksettings(port->dev, &ecmd);
+               err = netif_get_link_ksettings(port->dev, &ecmd);
                if (!err) {
                        port->state.speed = ecmd.base.speed;
                        port->state.duplex = ecmd.base.duplex;