This is a note to let you know that I've just added the patch titled
net: dsa: felix: don't use devres for mdiobus
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-felix-don-t-use-devres-for-mdiobus.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 286abaaa767bfdc77a64de82249948abda35b89f
Author: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Date: Mon Feb 7 18:15:50 2022 +0200
net: dsa: felix: don't use devres for mdiobus
[ Upstream commit 209bdb7ec6a28c7cdf580a0a98afbc9fc3b98932 ]
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 Felix VSC9959 switch is a PCI 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 felix 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 felix driver has the code structure in place for orderly mdiobus
removal, so just replace devm_mdiobus_alloc_size() 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@xxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index 2e5bbdca5ea47..cd8d9b0e0edb3 100644
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -1050,7 +1050,7 @@ static int vsc9959_mdio_bus_alloc(struct ocelot *ocelot)
return PTR_ERR(hw);
}
- bus = devm_mdiobus_alloc_size(dev, sizeof(*mdio_priv));
+ bus = mdiobus_alloc_size(sizeof(*mdio_priv));
if (!bus)
return -ENOMEM;
@@ -1070,6 +1070,7 @@ static int vsc9959_mdio_bus_alloc(struct ocelot *ocelot)
rc = mdiobus_register(bus);
if (rc < 0) {
dev_err(dev, "failed to register MDIO bus\n");
+ mdiobus_free(bus);
return rc;
}
@@ -1119,6 +1120,7 @@ static void vsc9959_mdio_bus_free(struct ocelot *ocelot)
lynx_pcs_destroy(pcs);
}
mdiobus_unregister(felix->imdio);
+ mdiobus_free(felix->imdio);
}
static void vsc9959_sched_speed_set(struct ocelot *ocelot, int port,
