On 10/16/19 12:53 PM, Heiner Kallweit wrote:
> Currently there's a bug in the module subsystem [0] preventing load of
> the PHY driver module on certain systems (as one symptom).
> This results in a NPE on such systems for the following reason:
> Instead of the correct PHY driver the genphy driver is loaded that
> doesn't implement the read_page/write_page callbacks. Every call to
> phy_read_paged() et al will result in a NPE therefore.
>
> In parallel to fixing the root cause we should make sure that this one
> and maybe similar issues in other subsystems don't result in a NPE
> in phylib. So let's check for the callbacks before using them and warn
> once if they are not available.
Everywhere else in the PHY library we tend to do:
if (!phydev->drv)
return -EIO;
maybe not the best choice for an error code, but we should be consistent.
Is the issue really that we do have a driver we are bound to, but
somehow we cannot resolve the read_page/write_page callbacks to a valid
function pointer?
>
> [0] https://marc.info/?t=157072642100001&r=1&w=2
>
> Signed-off-by: Heiner Kallweit <hkallwe...@gmail.com>
> ---
> drivers/net/phy/phy-core.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
> index 9412669b5..0ae1722ba 100644
> --- a/drivers/net/phy/phy-core.c
> +++ b/drivers/net/phy/phy-core.c
> @@ -689,11 +689,17 @@ EXPORT_SYMBOL_GPL(phy_modify_mmd);
>
> static int __phy_read_page(struct phy_device *phydev)
> {
> + if (WARN_ONCE(!phydev->drv->read_page, "read_page callback not
> available, PHY driver not loaded?\n"))
> + return -EOPNOTSUPP;
> +
> return phydev->drv->read_page(phydev);
> }
>
> static int __phy_write_page(struct phy_device *phydev, int page)
> {
> + if (WARN_ONCE(!phydev->drv->write_page, "write_page callback not
> available, PHY driver not loaded?\n"))
> + return -EOPNOTSUPP;
> +
> return phydev->drv->write_page(phydev, page);
> }
>
>
--
Florian
