"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 | 32 +++++++++++++++++++++++++++-----
1 file changed, 27 insertions(+), 5 deletions(-)
V6: overlooked format-path "1/2" when generating this patch.
V5: remove ax88772_mdio_unregister() call from error path in ax88772_init_phy()
Jakub pointed out ax88772_mdio_unregister() will get called twice.
(note: putting mdio handling in one function helps avoid this kind of bug.)
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..f7cff58fe044 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)
@@ -896,16 +910,23 @@ 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 +947,7 @@ 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
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:
On Tue, 21 Mar 2023 10:05:39 -0700 you 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.
>
> [...]
Here is the summary with links:
- [PATCHv6,net] net: asix: fix modprobe "sysfs: cannot create duplicate filename"
https://git.kernel.org/netdev/net/c/8eac0095de35
You are awesome, thank you!
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