net: mdiobus: get rid of a BUG_ON()

[ Upstream commit 1dde47a66d4fb181830d6fa000e5ea86907b639e ]

We spotted a bug recently during a review where a driver was
unregistering a bus that wasn't registered, which would trigger this
BUG_ON().  Let's handle that situation more gracefully, and just print
a warning and return.

Reported-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 757e950fb745bb4c5869c93f9669ee634de7843c..b848439fa837c607d52f3c01162d3134ad08d1a5 100644 (file)
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -608,7 +608,8 @@ void mdiobus_unregister(struct mii_bus *bus)
        struct mdio_device *mdiodev;
        int i;
 
-       BUG_ON(bus->state != MDIOBUS_REGISTERED);
+       if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
+               return;
        bus->state = MDIOBUS_UNREGISTERED;
 
        for (i = 0; i < PHY_MAX_ADDR; i++) {