> -----Original Message-----
> From: Florian Fainelli [mailto:f.faine...@gmail.com]
> Sent: Wednesday, February 08, 2017 3:38 PM
> To: netdev@vger.kernel.org
> Cc: da...@davemloft.net; and...@lunn.ch; rmk+ker...@armlinux.org.uk;
> maowenan; Florian Fainelli
> Subject: [PATCH net v2 1/3] net: phy: Fix PHY module checks
>
> 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;
Hi Florian,
Here "return -EIO" will miss decreasing bus->owner reference count.
Mao Wenan
> }
> @@ -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
