diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index 6405ce397baf..e851a67740f7 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -2234,20 +2234,25 @@ void bond_3ad_adapter_duplex_changed(struct slave *slave)
 
 	port = &(SLAVE_AD_INFO(slave).port);
 
-	// if slave is null, the whole port is not initialized
+	/* if slave is null, the whole port is not initialized */
 	if (!port->slave) {
 		pr_warning("%s: Warning: duplex changed for uninitialized port on %s\n",
 			   slave->bond->dev->name, slave->dev->name);
 		return;
 	}
 
+	__get_state_machine_lock(port);
+
 	port->actor_admin_port_key &= ~AD_DUPLEX_KEY_BITS;
 	port->actor_oper_port_key = port->actor_admin_port_key |=
 		__get_duplex(port);
 	pr_debug("Port %d changed duplex\n", port->actor_port_number);
-	// there is no need to reselect a new aggregator, just signal the
-	// state machines to reinitialize
+	/* there is no need to reselect a new aggregator, just signal the
+	 * state machines to reinitialize
+	 */
 	port->sm_vars |= AD_PORT_BEGIN;
+
+	__release_state_machine_lock(port);
 }
 
 /**