From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit 50facd86e9fbc4b93fe02e5fe05776047f45dbfb ]
As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres")
mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered.
The ar9331 is an MDIO device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here.
If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the ar9331 switch driver on shutdown.
So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all.
The ar9331 driver doesn't have a complex code structure for mdiobus removal, so just replace of_mdiobus_register with the devres variant in order to be all-devres and ensure that we don't free a still-registered bus.
Fixes: ac3a68d56651 ("net: phy: don't abuse devres in devm_mdiobus_register()") Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Reviewed-by: Florian Fainelli f.fainelli@gmail.com Tested-by: Oleksij Rempel o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/qca/ar9331.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/net/dsa/qca/ar9331.c b/drivers/net/dsa/qca/ar9331.c index 661745932a539..c33bdcf7efc58 100644 --- a/drivers/net/dsa/qca/ar9331.c +++ b/drivers/net/dsa/qca/ar9331.c @@ -289,7 +289,7 @@ static int ar9331_sw_mbus_init(struct ar9331_sw_priv *priv) if (!mnp) return -ENODEV;
- ret = of_mdiobus_register(mbus, mnp); + ret = devm_of_mdiobus_register(dev, mbus, mnp); of_node_put(mnp); if (ret) return ret; @@ -856,7 +856,6 @@ static void ar9331_sw_remove(struct mdio_device *mdiodev) struct ar9331_sw_priv *priv = dev_get_drvdata(&mdiodev->dev);
irq_domain_remove(priv->irqdomain); - mdiobus_unregister(priv->mbus); dsa_unregister_switch(&priv->ds);
reset_control_assert(priv->sw_reset);