On Mon, 24 Oct 2022 20:00:00 +0200 Thomas Osterried wrote:

 II) What consequences has the tracker counter?

     As far as I can see by kernel messages, the netdev tracker forces the
     kernel to wait
       (on ifdown (i.e. ifconfig ax0 down) 
        or rmmod (i.e. rmmod bpqether or rmmod ax25) )
     until all references to the network device are freed.
     If there's a bug (refcount > 0 or < 0), kernel obviously waits for ever.

Small correction here - the wait is when netdev is unregistered,
which often happens on rmmod, but also when user asks for a sw
netdev to be deleted, or HW device is removed, etc.

III) Is it only to track sessions initiated from userspace?

     I think no.

Correct, the trackers track the references taken on the device.
Doesn't really matter if the reference is somehow tracable to
a user request or not.

Sorry for lack of input on the actual ax25 problem, I had looked
briefly in September and it wasn't obvious how things work :S