[PATCH 2/2] net: macb: Unregister nedev before MDIO bus in remove

From: Claudiu Beznea
Date: Sun Nov 26 2023 - 09:15:03 EST


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 <claudiu.beznea@xxxxxxxxx>
---
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