This is a note to let you know that I've just added the patch titled
net: dsa: ar9331: register the mdiobus under devres
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-dsa-ar9331-register-the-mdiobus-under-devres.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0658be6107c731f0ffdd443501879a1b5e009cc6
Author: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Date: Mon Feb 7 18:15:48 2022 +0200
net: dsa: ar9331: register the mdiobus under devres
[ 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@xxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Tested-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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);
