Re: [Intel-wired-lan] [PATCH 1/5] idpf: skip getting/setting ring params if vport is NULL during HW reset

[Li Li]

Please reject this patch series given the underlying issue is fixed in
an earlier patch
series already, thanks.

On Wed, Jan 7, 2026 at 9:41 AM Tantilov, Emil S
<emil.s.tantilov@xxxxxxxxx> wrote:
>
>
>
> On 1/6/2026 5:04 PM, Li Li via Intel-wired-lan wrote:
> > When an idpf HW reset is triggered, it clears the vport but does
> > not clear the netdev held by vport:
> >
> >      // In idpf_vport_dealloc() called by idpf_init_hard_reset(),
> >      // idpf_init_hard_reset() sets IDPF_HR_RESET_IN_PROG, so
> >      // idpf_decfg_netdev() doesn't get called.
> >      if (!test_bit(IDPF_HR_RESET_IN_PROG, adapter->flags))
> >          idpf_decfg_netdev(vport);
> >      // idpf_decfg_netdev() would clear netdev but it isn't called:
> >      unregister_netdev(vport->netdev);
> >      free_netdev(vport->netdev);
> >      vport->netdev = NULL;
> >      // Later in idpf_init_hard_reset(), the vport is cleared:
> >      kfree(adapter->vports);
> >      adapter->vports = NULL;
> >
> > During an idpf HW reset, when "ethtool -g/-G" is called on the netdev,
> > the vport associated with the netdev is NULL, and so a kernel panic
> > would happen:
> >
> > [  513.185327] BUG: kernel NULL pointer dereference, address: 0000000000000038
> > ...
> > [  513.232756] RIP: 0010:idpf_get_ringparam+0x45/0x80
> >
> > This can be reproduced reliably by injecting a TX timeout to cause
> > an idpf HW reset, and injecting a virtchnl error to cause the HW
> > reset to fail and retry, while calling "ethtool -g/-G" on the netdev
> > at the same time.
>
> I have posted series that resolves these issues in the reset path by
> reshuffling the flow a bit and adding netif_device_detach/attach to
> make sure the netdevs are better protected in the middle of a reset:
> https://lore.kernel.org/intel-wired-lan/20251121001218.4565-1-emil.s.tantilov@xxxxxxxxx/
>
> If you are still seeing issues with the above applied, let me know and I
> can take a look.

Thanks Emil! Yes I performed the experiment at a commit past your
patch series above, and it
does look like the kernel panic does appear anymore. Now performing
ethtool commands during
HW resets would result in "netlink error: No such device", which is
expected because we are detaching
the netdev at the start of the HW reset.

Please reject this patch series, thanks!

>
> >
> > With this patch applied, we see the following error but no kernel
> > panics anymore:
> >
> > [  476.323630] idpf 0000:05:00.0 eth1: failed to get ring params due to no vport in netdev
> >
> > Signed-off-by: Li Li <boolli@xxxxxxxxxx>
> > ---
> >   drivers/net/ethernet/intel/idpf/idpf_ethtool.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
> > index d5711be0b8e69..6a4b630b786c2 100644
> > --- a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
> > +++ b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
> > @@ -639,6 +638,10 @@ static void idpf_get_ringparam(struct net_device *netdev,
> >
> >       idpf_vport_ctrl_lock(netdev);
> >       vport = idpf_netdev_to_vport(netdev);
> > +     if (!vport) {
>
> We used to have these all over the place, but the code was changed to
> rely on idpf_vport_ctrl_lock() for the protection of the vport state.
> Still some issues remain with the error paths (hence the series above),
> but in general we don't want to resort to vport NULL checks and rather
> fix the reset flows to rely on cleaner logic and locks.
>
> Thanks,
> Emil
>
> > +             netdev_err(netdev, "failed to get ring params due to no vport in netdev\n");
> > +             goto unlock;
> > +     }
> >
> >       ring->rx_max_pending = IDPF_MAX_RXQ_DESC;
> >       ring->tx_max_pending = IDPF_MAX_TXQ_DESC;
> > @@ -647,6 +651,7 @@ static void idpf_get_ringparam(struct net_device *netdev,
> >
> >       kring->tcp_data_split = idpf_vport_get_hsplit(vport);
> >
> > +unlock:
> >       idpf_vport_ctrl_unlock(netdev);
> >   }
> >
> > @@ -673,6 +674,11 @@ static int idpf_set_ringparam(struct net_device *netdev,
> >
> >       idpf_vport_ctrl_lock(netdev);
> >       vport = idpf_netdev_to_vport(netdev);
> > +     if (!vport) {
> > +             netdev_err(netdev, "ring params not changed due to no vport in netdev\n");
> > +             err = -EFAULT;
> > +             goto unlock_mutex;
> > +     }
> >
> >       idx = vport->idx;
> >
>