From: Vladimir Oltean vladimir.oltean@nxp.com
[ 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@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/ocelot/felix_vsc9959.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
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,