Re: [PATCH] ethtool: don't touch the parent device of a net device being unregistered

[Andrew Lunn]

On Sun, Mar 22, 2026 at 10:59:15AM +0300, Alexander Popov wrote:
> The ethtool operations may be performed on a net device that is currently
> being unregistered. This is also described in the commit dde91ccfa25fd58f
> ("ethtool: do not perform operations on net devices being unregistered").
> Moreover, such a device may have a parent that has already been freed.

I don't know the device core too well, but can you explain in the
example stack trace you gave how the parent can already be free? I
would of expected devices are arranged in a tree, and free happens
from the leaves towards the root? In order to do a clean shutdown, you
might need to perform operations on the parent.

I just want to make sure this is not a broken parent device which
should be fixed...

       Andrew