[v2,net] ixgbevf: fix invalid uses of napi_hash_del()

From: Eric Dumazet <edumazet@google.com>

Calling napi_hash_del() before netif_napi_del() is dangerous
if a synchronize_rcu() is not enforced before NAPI struct freeing.

Lets leave this detail to core networking stack to get it right.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    6 ------
 1 file changed, 6 deletions(-)

On Wed, 2016-11-16 at 07:26 -0800, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> Calling napi_hash_del() before netif_napi_del() is dangerous
> if a synchronize_rcu() is not enforced before NAPI struct freeing.
> 
> Lets leave this detail to core networking stack to get it right.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> index 7eaac3234049..bf4d7efc7dbd 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> @@ -2511,9 +2511,6 @@ static int ixgbevf_alloc_q_vectors(struct ixgbevf_adapter *adapter)
>  	while (q_idx) {
>  		q_idx--;
>  		q_vector = adapter->q_vector[q_idx];
> -#ifdef CONFIG_NET_RX_BUSY_POLL
> -		napi_hash_del(&q_vector->napi);
> -#endif
>  		netif_napi_del(&q_vector->napi);
>  		kfree(q_vector);
>  		adapter->q_vector[q_idx] = NULL;
> @@ -2537,9 +2534,6 @@ static void ixgbevf_free_q_vectors(struct ixgbevf_adapter *adapter)
>  		struct ixgbevf_q_vector *q_vector = adapter->q_vector[q_idx];
>  
>  		adapter->q_vector[q_idx] = NULL;
> -#ifdef CONFIG_NET_RX_BUSY_POLL
> -		napi_hash_del(&q_vector->napi);
> -#endif
>  		netif_napi_del(&q_vector->napi);
>  		kfree(q_vector);
>  	}
> 
> 

It looks this patch was not picked up ?

Thanks !

On Sat, 2016-12-03 at 07:00 -0800, Eric Dumazet wrote:
> On Wed, 2016-11-16 at 07:26 -0800, Eric Dumazet wrote:
> > From: Eric Dumazet <edumazet@google.com>
> > 
> > Calling napi_hash_del() before netif_napi_del() is dangerous
> > if a synchronize_rcu() is not enforced before NAPI struct freeing.
> > 
> > Lets leave this detail to core networking stack to get it right.
> > 
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
> > Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> > ---
> >   drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    6 ------
> >   1 file changed, 6 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> > index 7eaac3234049..bf4d7efc7dbd 100644
> > --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> > +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> > @@ -2511,9 +2511,6 @@ static int ixgbevf_alloc_q_vectors(struct
> > ixgbevf_adapter *adapter)
> >        while (q_idx) {
> >                q_idx--;
> >                q_vector = adapter->q_vector[q_idx];
> > -#ifdef CONFIG_NET_RX_BUSY_POLL
> > -             napi_hash_del(&q_vector->napi);
> > -#endif
> >                netif_napi_del(&q_vector->napi);
> >                kfree(q_vector);
> >                adapter->q_vector[q_idx] = NULL;
> > @@ -2537,9 +2534,6 @@ static void ixgbevf_free_q_vectors(struct
> > ixgbevf_adapter *adapter)
> >                struct ixgbevf_q_vector *q_vector = adapter-
> > >q_vector[q_idx];
> >   
> >                adapter->q_vector[q_idx] = NULL;
> > -#ifdef CONFIG_NET_RX_BUSY_POLL
> > -             napi_hash_del(&q_vector->napi);
> > -#endif
> >                netif_napi_del(&q_vector->napi);
> >                kfree(q_vector);
> >        }
> > 
> > 
> 
> It looks this patch was not picked up ?

Yeah, sorry I missed it since it was not sent to intel-wired-lan mailing
list.  Dave I am fine if you want to pick this up for your net tree (if it
is not too late).