"modprobe asix ; rmmod asix ; modprobe asix" fails with:
sysfs: cannot create duplicate filename \
'/devices/virtual/mdio_bus/usb-003:004'
Issue was originally reported by Anton Lundin on 2022-06-22 (link below).
Chrome OS team hit the same issue in Feb, 2023 when trying to find
work arounds for other issues with AX88172 devices.
The use of devm_mdiobus_register() with usbnet devices results in the
MDIO data being associated with the USB device. When the asix driver
is unloaded, the USB device continues to exist and the corresponding
"mdiobus_unregister()" is NOT called until the USB device is unplugged
or unauthorized. So the next "modprobe asix" will fail because the MDIO
phy sysfs attributes still exist.
The 'easy' (from a design PoV) fix is to use the non-devm variants of
mdiobus_* functions and explicitly manage this use in the asix_bind
and asix_unbind function calls. I've not explored trying to fix usbnet
initialization so devm_* stuff will work.
Fixes: e532a096be0e5 ("net: usb: asix: ax88772: add phylib support")
Reported-by: Anton Lundin <[email protected]>
Link: https://lore.kernel.org/netdev/[email protected]/T/
Tested-by: Eizan Miyamoto <[email protected]>
Signed-off-by: Grant Grundler <[email protected]>
---
drivers/net/usb/asix_devices.c | 33 ++++++++++++++++++++++++++++-----
1 file changed, 28 insertions(+), 5 deletions(-)
V4: add mdio_unregister to ax88172_bind() error handling paths
V3: rebase against netdev/net.git
remove "TEST" prefix in subject line
added Link: tag for Reported-by tag
V2: moved mdiobus_get_phy() call back into ax88772_init_phy()
(Lukas Wunner is entirely correct this patch is much easier
to backport without this patch hunk.)
Added "Fixes:" tag per request from Florian Fainelli
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 743cbf5d662c..b758010bab36 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -666,8 +666,9 @@ static int asix_resume(struct usb_interface *intf)
static int ax88772_init_mdio(struct usbnet *dev)
{
struct asix_common_private *priv = dev->driver_priv;
+ int ret;
- priv->mdio = devm_mdiobus_alloc(&dev->udev->dev);
+ priv->mdio = mdiobus_alloc();
if (!priv->mdio)
return -ENOMEM;
@@ -679,7 +680,20 @@ static int ax88772_init_mdio(struct usbnet *dev)
snprintf(priv->mdio->id, MII_BUS_ID_SIZE, "usb-%03d:%03d",
dev->udev->bus->busnum, dev->udev->devnum);
- return devm_mdiobus_register(&dev->udev->dev, priv->mdio);
+ ret = mdiobus_register(priv->mdio);
+ if (ret) {
+ netdev_err(dev->net, "Could not register MDIO bus (err %d)\n", ret);
+ mdiobus_free(priv->mdio);
+ priv->mdio = NULL;
+ }
+
+ return ret;
+}
+
+static void ax88772_mdio_unregister(struct asix_common_private *priv)
+{
+ mdiobus_unregister(priv->mdio);
+ mdiobus_free(priv->mdio);
}
static int ax88772_init_phy(struct usbnet *dev)
@@ -690,6 +704,7 @@ static int ax88772_init_phy(struct usbnet *dev)
priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr);
if (!priv->phydev) {
netdev_err(dev->net, "Could not find PHY\n");
+ ax88772_mdio_unregister(priv);
return -ENODEV;
}
@@ -896,16 +911,23 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
ret = ax88772_init_mdio(dev);
if (ret)
- return ret;
+ goto mdio_err;
ret = ax88772_phylink_setup(dev);
if (ret)
- return ret;
+ goto phylink_err;
ret = ax88772_init_phy(dev);
if (ret)
- phylink_destroy(priv->phylink);
+ goto initphy_err;
+ return 0;
+
+initphy_err:
+ phylink_destroy(priv->phylink);
+phylink_err:
+ ax88772_mdio_unregister(priv);
+mdio_err:
return ret;
}
@@ -926,6 +948,7 @@ static void ax88772_unbind(struct usbnet *dev, struct usb_interface *intf)
phylink_disconnect_phy(priv->phylink);
rtnl_unlock();
phylink_destroy(priv->phylink);
+ ax88772_mdio_unregister(priv);
asix_rx_fixup_common_free(dev->driver_priv);
}
--
2.40.0.rc1.284.g88254d51c5-goog
On Mon, Mar 13, 2023 at 10:54:10PM -0700, Grant Grundler wrote:
> "modprobe asix ; rmmod asix ; modprobe asix" fails with:
> sysfs: cannot create duplicate filename \
> '/devices/virtual/mdio_bus/usb-003:004'
>
> Issue was originally reported by Anton Lundin on 2022-06-22 (link below).
>
> Chrome OS team hit the same issue in Feb, 2023 when trying to find
> work arounds for other issues with AX88172 devices.
>
> The use of devm_mdiobus_register() with usbnet devices results in the
> MDIO data being associated with the USB device. When the asix driver
> is unloaded, the USB device continues to exist and the corresponding
> "mdiobus_unregister()" is NOT called until the USB device is unplugged
> or unauthorized. So the next "modprobe asix" will fail because the MDIO
> phy sysfs attributes still exist.
>
> The 'easy' (from a design PoV) fix is to use the non-devm variants of
> mdiobus_* functions and explicitly manage this use in the asix_bind
> and asix_unbind function calls. I've not explored trying to fix usbnet
> initialization so devm_* stuff will work.
>
> Fixes: e532a096be0e5 ("net: usb: asix: ax88772: add phylib support")
> Reported-by: Anton Lundin <[email protected]>
> Link: https://lore.kernel.org/netdev/[email protected]/T/
> Tested-by: Eizan Miyamoto <[email protected]>
> Signed-off-by: Grant Grundler <[email protected]>
>
> ---
> drivers/net/usb/asix_devices.c | 33 ++++++++++++++++++++++++++++-----
> 1 file changed, 28 insertions(+), 5 deletions(-)
>
> V4: add mdio_unregister to ax88172_bind() error handling paths
>
> V3: rebase against netdev/net.git
> remove "TEST" prefix in subject line
> added Link: tag for Reported-by tag
>
> V2: moved mdiobus_get_phy() call back into ax88772_init_phy()
> (Lukas Wunner is entirely correct this patch is much easier
> to backport without this patch hunk.)
> Added "Fixes:" tag per request from Florian Fainelli
>
> diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
> index 743cbf5d662c..b758010bab36 100644
> --- a/drivers/net/usb/asix_devices.c
> +++ b/drivers/net/usb/asix_devices.c
> @@ -666,8 +666,9 @@ static int asix_resume(struct usb_interface *intf)
> static int ax88772_init_mdio(struct usbnet *dev)
> {
> struct asix_common_private *priv = dev->driver_priv;
> + int ret;
>
> - priv->mdio = devm_mdiobus_alloc(&dev->udev->dev);
Hi,
Patch looks good, one question, are the devm_mdiobus_alloc() and
devm_mdiobus_register functions used anywhere after removing? Maybe it
is worth to remove also the implementation if it isn't used.
Otherwise
Reviewed-by: Michal Swiatkowski <[email protected]>
> + priv->mdio = mdiobus_alloc();
> if (!priv->mdio)
> return -ENOMEM;
>
> @@ -679,7 +680,20 @@ static int ax88772_init_mdio(struct usbnet *dev)
> snprintf(priv->mdio->id, MII_BUS_ID_SIZE, "usb-%03d:%03d",
> dev->udev->bus->busnum, dev->udev->devnum);
>
> - return devm_mdiobus_register(&dev->udev->dev, priv->mdio);
> + ret = mdiobus_register(priv->mdio);
> + if (ret) {
> + netdev_err(dev->net, "Could not register MDIO bus (err %d)\n", ret);
> + mdiobus_free(priv->mdio);
> + priv->mdio = NULL;
> + }
> +
> + return ret;
> +}
> +
> +static void ax88772_mdio_unregister(struct asix_common_private *priv)
> +{
> + mdiobus_unregister(priv->mdio);
> + mdiobus_free(priv->mdio);
> }
>
> static int ax88772_init_phy(struct usbnet *dev)
> @@ -690,6 +704,7 @@ static int ax88772_init_phy(struct usbnet *dev)
> priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr);
> if (!priv->phydev) {
> netdev_err(dev->net, "Could not find PHY\n");
> + ax88772_mdio_unregister(priv);
> return -ENODEV;
> }
>
> @@ -896,16 +911,23 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
>
> ret = ax88772_init_mdio(dev);
> if (ret)
> - return ret;
> + goto mdio_err;
>
> ret = ax88772_phylink_setup(dev);
> if (ret)
> - return ret;
> + goto phylink_err;
>
> ret = ax88772_init_phy(dev);
> if (ret)
> - phylink_destroy(priv->phylink);
> + goto initphy_err;
>
> + return 0;
> +
> +initphy_err:
> + phylink_destroy(priv->phylink);
> +phylink_err:
> + ax88772_mdio_unregister(priv);
> +mdio_err:
> return ret;
> }
>
> @@ -926,6 +948,7 @@ static void ax88772_unbind(struct usbnet *dev, struct usb_interface *intf)
> phylink_disconnect_phy(priv->phylink);
> rtnl_unlock();
> phylink_destroy(priv->phylink);
> + ax88772_mdio_unregister(priv);
> asix_rx_fixup_common_free(dev->driver_priv);
> }
>
> --
> 2.40.0.rc1.284.g88254d51c5-goog
>
On Mon, 13 Mar 2023 22:54:10 -0700 Grant Grundler wrote:
> @@ -690,6 +704,7 @@ static int ax88772_init_phy(struct usbnet *dev)
> priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr);
> if (!priv->phydev) {
> netdev_err(dev->net, "Could not find PHY\n");
> + ax88772_mdio_unregister(priv);
this line needs to go now..
> return -ENODEV;
.. since if we return error here ..
> }
>
> @@ -896,16 +911,23 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
>
> ret = ax88772_init_mdio(dev);
> if (ret)
> - return ret;
> + goto mdio_err;
>
> ret = ax88772_phylink_setup(dev);
> if (ret)
> - return ret;
> + goto phylink_err;
>
> ret = ax88772_init_phy(dev);
.. it will pop out here ..
> if (ret)
> - phylink_destroy(priv->phylink);
> + goto initphy_err;
>
> + return 0;
> +
> +initphy_err:
> + phylink_destroy(priv->phylink);
> +phylink_err:
> + ax88772_mdio_unregister(priv);
.. and then call ax88772_mdio_unregister() a second time.
> +mdio_err:
> return ret;
> }
On Wed, Mar 15, 2023 at 10:08 PM Jakub Kicinski <[email protected]> wrote:
>
> On Mon, 13 Mar 2023 22:54:10 -0700 Grant Grundler wrote:
> > @@ -690,6 +704,7 @@ static int ax88772_init_phy(struct usbnet *dev)
> > priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr);
> > if (!priv->phydev) {
> > netdev_err(dev->net, "Could not find PHY\n");
> > + ax88772_mdio_unregister(priv);
>
> this line needs to go now..
>
> > return -ENODEV;
>
> .. since if we return error here ..
>
> > }
> >
> > @@ -896,16 +911,23 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
> >
> > ret = ax88772_init_mdio(dev);
> > if (ret)
> > - return ret;
> > + goto mdio_err;
> >
> > ret = ax88772_phylink_setup(dev);
> > if (ret)
> > - return ret;
> > + goto phylink_err;
> >
> > ret = ax88772_init_phy(dev);
>
> .. it will pop out here ..
>
> > if (ret)
> > - phylink_destroy(priv->phylink);
> > + goto initphy_err;
> >
> > + return 0;
> > +
> > +initphy_err:
> > + phylink_destroy(priv->phylink);
> > +phylink_err:
> > + ax88772_mdio_unregister(priv);
>
> .. and then call ax88772_mdio_unregister() a second time.
Doh! Yes - good catch. Let me fix that.
cheers,
grant
>
> > +mdio_err:
> > return ret;
> > }