diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index b44a6aeb346d0404144dde0304a502268de1da91..165a8009c640100c45d5022575bedb0c88af1a04 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -322,6 +322,11 @@ static u16 __get_link_speed(struct port *port)
 
 		default:
 			/* unknown speed value from ethtool. shouldn't happen */
+			if (slave->speed != SPEED_UNKNOWN)
+				pr_warn_once("%s: unknown ethtool speed (%d) for port %d (set it to 0)\n",
+					     slave->bond->dev->name,
+					     slave->speed,
+					     port->actor_port_number);
 			speed = 0;
 			break;
 		}