From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit 08f1a20822349004bb9cc1b153ecb516e9f2889d ]
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 Starfighter 2 is a platform 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 bcm_sf2 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 bcm_sf2 driver has the code structure in place for orderly mdiobus removal, so just replace devm_mdiobus_alloc() with the non-devres variant, and add manual free where necessary, to ensure that we don't let devres 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 Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/bcm_sf2.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/dsa/bcm_sf2.c b/drivers/net/dsa/bcm_sf2.c index 690e9d9495e75..08a675a5328d7 100644 --- a/drivers/net/dsa/bcm_sf2.c +++ b/drivers/net/dsa/bcm_sf2.c @@ -504,7 +504,7 @@ static int bcm_sf2_mdio_register(struct dsa_switch *ds) get_device(&priv->master_mii_bus->dev); priv->master_mii_dn = dn;
- priv->slave_mii_bus = devm_mdiobus_alloc(ds->dev); + priv->slave_mii_bus = mdiobus_alloc(); if (!priv->slave_mii_bus) { of_node_put(dn); return -ENOMEM; @@ -564,8 +564,10 @@ static int bcm_sf2_mdio_register(struct dsa_switch *ds) }
err = mdiobus_register(priv->slave_mii_bus); - if (err && dn) + if (err && dn) { + mdiobus_free(priv->slave_mii_bus); of_node_put(dn); + }
return err; } @@ -573,6 +575,7 @@ static int bcm_sf2_mdio_register(struct dsa_switch *ds) static void bcm_sf2_mdio_unregister(struct bcm_sf2_priv *priv) { mdiobus_unregister(priv->slave_mii_bus); + mdiobus_free(priv->slave_mii_bus); of_node_put(priv->master_mii_dn); }