From: Vladimir Oltean vladimir.oltean@nxp.com
stable inclusion from stable-v5.10.101 commit e177d2e85ebcd3008c4b2abc293f4118e04eedef bugzilla: https://gitee.com/openeuler/kernel/issues/I5669Z
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 0d120dfb5d67edc5bcd1804e167dba2b30809afd ]
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 GSWIP switch 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 GSWIP 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 gswip 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 Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/net/dsa/lantiq_gswip.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c index 4d23a7aba796..ed517985ca88 100644 --- a/drivers/net/dsa/lantiq_gswip.c +++ b/drivers/net/dsa/lantiq_gswip.c @@ -495,8 +495,9 @@ static int gswip_mdio_rd(struct mii_bus *bus, int addr, int reg) static int gswip_mdio(struct gswip_priv *priv, struct device_node *mdio_np) { struct dsa_switch *ds = priv->ds; + int err;
- ds->slave_mii_bus = devm_mdiobus_alloc(priv->dev); + ds->slave_mii_bus = mdiobus_alloc(); if (!ds->slave_mii_bus) return -ENOMEM;
@@ -509,7 +510,11 @@ static int gswip_mdio(struct gswip_priv *priv, struct device_node *mdio_np) ds->slave_mii_bus->parent = priv->dev; ds->slave_mii_bus->phy_mask = ~ds->phys_mii_mask;
- return of_mdiobus_register(ds->slave_mii_bus, mdio_np); + err = of_mdiobus_register(ds->slave_mii_bus, mdio_np); + if (err) + mdiobus_free(ds->slave_mii_bus); + + return err; }
static int gswip_pce_table_entry_read(struct gswip_priv *priv, @@ -2086,8 +2091,10 @@ static int gswip_probe(struct platform_device *pdev) gswip_mdio_mask(priv, GSWIP_MDIO_GLOB_ENABLE, 0, GSWIP_MDIO_GLOB); dsa_unregister_switch(priv->ds); mdio_bus: - if (mdio_np) + if (mdio_np) { mdiobus_unregister(priv->ds->slave_mii_bus); + mdiobus_free(priv->ds->slave_mii_bus); + } put_mdio_node: of_node_put(mdio_np); for (i = 0; i < priv->num_gphy_fw; i++) @@ -2107,6 +2114,7 @@ static int gswip_remove(struct platform_device *pdev)
if (priv->ds->slave_mii_bus) { mdiobus_unregister(priv->ds->slave_mii_bus); + mdiobus_free(priv->ds->slave_mii_bus); of_node_put(priv->ds->slave_mii_bus->dev.of_node); }