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. [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); } -- 2.23.0
