[PATCH net v2 1/3] net: phy: Fix PHY module checks

[Florian Fainelli]

The Generic PHY drivers gets assigned after we checked that the current PHY
driver is NULL, so we need to check a few things before we can safely
derference d->driver. Update phy_attach_direct() and phy_detach() accordingly
to be resilient to these cases.

Even though the Generic PHY driver defaults to phy_probe() which can hardly
fail at the moment, let's fix the label so we don't call phy_detach() on a
network device we have not attached yet.

Fixes: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver")
Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
 drivers/net/phy/phy_device.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 0d8f4d3847f6..bde240bf8d7b 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -920,7 +920,7 @@ int phy_attach_direct(struct net_device *dev, struct 
phy_device *phydev,
                return -EIO;
        }
 
-       if (!try_module_get(d->driver->owner)) {
+       if (d->driver && !try_module_get(d->driver->owner)) {
                dev_err(&dev->dev, "failed to get the device driver module\n");
                return -EIO;
        }
@@ -943,7 +943,7 @@ int phy_attach_direct(struct net_device *dev, struct 
phy_device *phydev,
                        err = device_bind_driver(d);
 
                if (err)
-                       goto error;
+                       goto error_put_device;
        }
 
        if (phydev->attached_dev) {
@@ -981,6 +981,7 @@ int phy_attach_direct(struct net_device *dev, struct 
phy_device *phydev,
 
 error:
        phy_detach(phydev);
+error_put_device:
        put_device(d);
        module_put(d->driver->owner);
        if (ndev_owner != bus->owner)
@@ -1065,7 +1066,8 @@ void phy_detach(struct phy_device *phydev)
        bus = phydev->mdio.bus;
 
        put_device(&phydev->mdio.dev);
-       module_put(phydev->mdio.dev.driver->owner);
+       if (phydev->mdio.dev.driver)
+               module_put(phydev->mdio.dev.driver->owner);
        if (ndev_owner != bus->owner)
                module_put(bus->owner);
 }
-- 
2.9.3