Hi,
This series tries to address stack traces printed when unbinding the
macb driver.
Thank you,
Claudiu Beznea
Claudiu Beznea (2):
net: phy: Check phydev->drv before dereferencing it
net: macb: Unregister nedev before MDIO bus in remove
drivers/net/ethernet/cadence/macb_main.c | 2 +-
drivers/net/phy/phy.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--
2.39.2
unregister_netdev() calls the struct net_device_ops::ndo_stop function,
which in the case of the macb driver is macb_close(). macb_close() calls,
in turn, PHY-specific APIs (e.g., phy_detach()). The call trace is as
follows:
macb_close() ->
phylink_disconnect_phy() ->
phy_disconnect() ->
phy_detach()
phy_detach() will remove associated sysfs files by calling
kernfs_remove_by_name_ns(), which will hit
"kernfs: cannot remove 'attached_dev', no directory" WARN(), which will
throw a stack trace too.
To avoid this, call unregiser_netdev() before mdiobus_unregister() and
mdiobus_free().
Fixes: 7897b071ac3b ("net: macb: convert to phylink")
Signed-off-by: Claudiu Beznea <[email protected]>
---
drivers/net/ethernet/cadence/macb_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index cebae0f418f2..73d041af3de1 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -5165,11 +5165,11 @@ static void macb_remove(struct platform_device *pdev)
if (dev) {
bp = netdev_priv(dev);
+ unregister_netdev(dev);
phy_exit(bp->sgmii_phy);
mdiobus_unregister(bp->mii_bus);
mdiobus_free(bp->mii_bus);
- unregister_netdev(dev);
tasklet_kill(&bp->hresp_err_tasklet);
pm_runtime_disable(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
--
2.39.2
The macb driver calls mdiobus_unregister() and mdiobus_free() in its remove
function before calling unregister_netdev(). unregister_netdev() calls the
driver-specific struct net_device_ops::ndo_stop function (macb_close()),
and macb_close() calls phylink_disconnect_phy(). This, in turn, will call:
phy_disconnect() ->
phy_free_interrupt() ->
phy_disable_interrupts() ->
phy_config_interrupt()
which dereference phydev->drv, which was already freed by:
mdiobus_unregister() ->
phy_mdio_device_remove() ->
device_del() ->
bus_remove_device() ->
device_release_driver_internal() ->
phy_remove()
from macb_close().
Although the sequence in the macb driver is not correct, check phydev->drv
before dereferencing it in phy_config_interrupt() to avoid scenarios
like the one described.
Fixes: 00db8189d984 ("This patch adds a PHY Abstraction Layer to the Linux Kernel")
Signed-off-by: Claudiu Beznea <[email protected]>
---
drivers/net/phy/phy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index a5fa077650e8..dd98a4b3ef81 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -165,7 +165,7 @@ EXPORT_SYMBOL_GPL(phy_get_rate_matching);
static int phy_config_interrupt(struct phy_device *phydev, bool interrupts)
{
phydev->interrupts = interrupts ? 1 : 0;
- if (phydev->drv->config_intr)
+ if (phydev->drv && phydev->drv->config_intr)
return phydev->drv->config_intr(phydev);
return 0;
--
2.39.2