From a5cf5ce92ecefcbeb3265e6f894905ab3ed5c4c2 Mon Sep 17 00:00:00 2001 From: Srinivas Kandagatla Date: Thu, 30 Aug 2012 05:49:58 +0000 Subject: [PATCH] net:stmmac: Add check if mdiobus is registered in stmmac_mdio_unregister This patch adds a basic check in stmmac_mdio_unregister to see if mdio bus registeration for this driver was actually sucessfull or not. Use case here is, if BSP considers using mdio-gpio bus along with stmmac driver by passing mdio_bus_data as NULL in platform data. Call to stmmac_mdio_register with mdio_bus_data as NULL returns 0, which is a considered sucessfull call form stmmac. Then again when we unload the driver we just call stmmac_mdio_unregister, this is were the actual problem is stmmac-mdio code dont really know at this instance of calling that stmmac_mdio_register was actually successful. So Adding a check in stmmac_mdio_unregister is always safe. Without this patch stmmac driver calls stmmac_mdio_register from stmmac_release which Segfaults as mii bus was never registered at the first point. Originally the this bug was found when unloading an stmmac driver instance which uses mdio-gpio for smi access. Signed-off-by: Srinivas Kandagatla Signed-off-by: David S. Miller --- drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c index ade1082..e1f3d04 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c @@ -258,6 +258,9 @@ int stmmac_mdio_unregister(struct net_device *ndev) { struct stmmac_priv *priv = netdev_priv(ndev); + if (!priv->mii) + return 0; + mdiobus_unregister(priv->mii); priv->mii->priv = NULL; mdiobus_free(priv->mii); -- 2.7.4