| Message ID | 20230317181321.3867173-1-grundler@chromium.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [PATCHv5,net,1/2] net: asix: fix modprobe "sysfs: cannot create duplicate filename" | expand |
On Fri, Mar 17, 2023 at 11:13:21AM -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 <glance@acc.umu.se> > Link: https://lore.kernel.org/netdev/20220623063649.GD23685@pengutronix.de/T/ > Tested-by: Eizan Miyamoto <eizan@chromium.org> > Signed-off-by: Grant Grundler <grundler@chromium.org> Reviewed-by: Simon Horman <simon.horman@corigine.com>
On Fri, 17 Mar 2023 11:13:21 -0700 Grant Grundler wrote: > "modprobe asix ; rmmod asix ; modprobe asix" fails with: > sysfs: cannot create duplicate filename \ > '/devices/virtual/mdio_bus/usb-003:004' Code looks good but now you posted only one patch with [PATCH 1/2] so patchwork is dutifully waiting to receive [PATCH 2/2]. And not running any checks. One more time, please :) You can keep Simon's review tag.
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); }
"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 <glance@acc.umu.se> Link: https://lore.kernel.org/netdev/20220623063649.GD23685@pengutronix.de/T/ Tested-by: Eizan Miyamoto <eizan@chromium.org> Signed-off-by: Grant Grundler <grundler@chromium.org> --- drivers/net/usb/asix_devices.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) 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