From: Florian Fainelli f.fainelli@gmail.com
commit 744d23c71af39c7dc77ac7c3cac87ae86a181a85 upstream.
Calling mdio_bus_phy_resume() with neither the PHY state machine set to PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication that we can produce a race condition looking like this:
CPU0 CPU1 bcmgenet_resume -> phy_resume -> phy_init_hw -> phy_start -> phy_resume phy_start_aneg() mdio_bus_phy_resume -> phy_resume -> phy_write(..., BMCR_RESET) -> usleep() -> phy_read()
with the phy_resume() function triggering a PHY behavior that might have to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix brcm_fet_config_init()") for instance) that ultimately leads to an error reading from the PHY.
Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM") Signed-off-by: Florian Fainelli f.fainelli@gmail.com Link: https://lore.kernel.org/r/20220801233403.258871-1-f.fainelli@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/phy/phy_device.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -316,6 +316,12 @@ static __maybe_unused int mdio_bus_phy_r
phydev->suspended_by_mdio_bus = 0;
+ /* If we managed to get here with the PHY state machine in a state other + * than PHY_HALTED this is an indication that something went wrong and + * we should most likely be using MAC managed PM and we are not. + */ + WARN_ON(phydev->state != PHY_HALTED && !phydev->mac_managed_pm); + ret = phy_init_hw(phydev); if (ret < 0) return ret;