Re: [PATCH net] hv_netvsc: Switch VF namespace in netvsc_open instead

[Jakub Kicinski <kuba@kernel.org>]

On Fri, 11 Jul 2025 13:57:10 -0700 Haiyang Zhang wrote:
> The existing code move the VF NIC to new namespace when NETDEV_REGISTER is
> received on netvsc NIC. During deletion of the namespace,
> default_device_exit_batch() >> default_device_exit_net() is called. When
> netvsc NIC is moved back and registered to the default namespace, it
> automatically brings VF NIC back to the default namespace. This will cause
> the default_device_exit_net() >> for_each_netdev_safe loop unable to detect
> the list end, and hit NULL ptr:

Are you saying that when netns is dismantled both devices are listed
for moving back to default, but the netvsc_event_set_vf_ns() logic
tries to undo the move / move the VF before the netns dismantle loop
got to it?

This needs a better fix, moving on open is way too hacky. 
Perhaps we should start with reverting 4c262801ea60 and then trying
to implement it in a more robust way?
-- 
pw-bot: cr