> -----Original Message-----
> From: Jakub Kicinski <[email protected]>
> Sent: Monday, July 14, 2025 9:29 PM
> To: Haiyang Zhang <[email protected]>
> Cc: [email protected]; [email protected]; Haiyang Zhang
> <[email protected]>; KY Srinivasan <[email protected]>;
> [email protected]; Dexuan Cui <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected]; linux-
> [email protected]; [email protected]
> Subject: [EXTERNAL] Re: [PATCH net] hv_netvsc: Switch VF namespace in
> netvsc_open instead
>
> 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?
netvsc_event_set_vf_ns() moves the VF to default ns before the netns
dismantle loop got to it, and causes the Null prt error.
> 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?
This patch reverts the 4c262801ea60, and moves the logic to netvsc_open().
I was thinking some other ways too... But seems I couldn't find a way
to know it's in the for_each_netdev_safe loop, and to skip moving the
VF in netvsc_event_set_vf_ns() this case.
Thanks,
- Haiyang
