tree eee88d8cc491a121d8c587caebd7503fd5bb03e5
parent 075ad765ef7541b2860de8408c165a92b78aefa3
author Florian Fainelli <f.fainelli@gmail.com> 1486609526 -0800
committer David S. Miller <davem@davemloft.net> 1486675332 -0500

net: phy: Fix PHY module checks and NULL deref in phy_attach_direct()

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 dereference d->driver. This would be causing a NULL deference to
occur when a system binds to the Generic PHY driver. Update
phy_attach_direct() to do the following:

- grab the driver module reference after we have assigned the Generic
  PHY drivers accordingly, and remember we came from the generic PHY
  path

- update the error path to clean up the module reference in case the
  Generic PHY probe function fails

- split the error path involving phy_detacht() to avoid double free/put
  since phy_detach() does all the clean up

- finally, have phy_detach() drop the module reference count before we
  call device_release_driver() for the Generic PHY driver case

Fixes: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>