Re: [PATCH net-next v2 05/11] net: bonding: don't recurse on the slave's netdev ops lock

[Nicolai Buchwitz <nb@tipi-net.de>]

Hi Jakub

On 3.6.2026 03:28, Jakub Kicinski wrote:
> bond_update_speed_duplex() calls __ethtool_get_link_ksettings() on
> the slave, which will soon take the slave's ops lock. One of its
> callers already holds it and the other three don't, so the function
> would either deadlock or run unprotected depending on the path.
> 
> Make the helper expect the slave's ops lock held and switch to
> netif_get_link_ksettings(). Wrap the three call sites that don't
> already hold it:
> 
>   * bond_enslave() (rtnl held; core drops the lower's ops lock
>     around ->ndo_add_slave).
>   * bond_miimon_commit() (rtnl_trylock'd from the mii workqueue).
>   * bond_ethtool_get_link_ksettings() (rtnl held via ethtool layer,
>     bond device itself is not ops locked).
> 
> The call site which does already hold the ops lock is
> bond_slave_netdev_event() via NETDEV_UP / NETDEV_CHANGE notifiers,
> so it stays as-is.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>

> [...]

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks
Nicolai