On 30.12.2018 23:21, Willem de Bruijn wrote:
> From: Willem de Bruijn <will...@google.com>
>
> The BPF flow dissector expects either skb->sk or skb->dev set on
> all skbs. Delay flow dissection until after skb->dev is set.
>
> This requires calling from within an rcu read-side critical section.
> That is fine, see also the call from tun_xdp_one.
>
> Fixes: d0e13a1488ad ("flow_dissector: lookup netns by skb->sk if skb->dev is
> NULL")
> Reported-by: Christian Borntraeger <borntrae...@de.ibm.com>
> Signed-off-by: Willem de Bruijn <will...@google.com>
Already too late, but
Tested-by: Christian Borntraeger <borntrae...@de.ibm.com>
> ---
> drivers/net/tap.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/net/tap.c b/drivers/net/tap.c
> index 443b2694130c..c0b52e48f0e6 100644
> --- a/drivers/net/tap.c
> +++ b/drivers/net/tap.c
> @@ -1177,8 +1177,6 @@ static int tap_get_user_xdp(struct tap_queue *q, struct
> xdp_buff *xdp)
> goto err_kfree;
> }
>
> - skb_probe_transport_header(skb, ETH_HLEN);
> -
> /* Move network header to the right position for VLAN tagged packets */
> if ((skb->protocol == htons(ETH_P_8021Q) ||
> skb->protocol == htons(ETH_P_8021AD)) &&
> @@ -1189,6 +1187,7 @@ static int tap_get_user_xdp(struct tap_queue *q, struct
> xdp_buff *xdp)
> tap = rcu_dereference(q->tap);
> if (tap) {
> skb->dev = tap->dev;
> + skb_probe_transport_header(skb, ETH_HLEN);
> dev_queue_xmit(skb);
> } else {
> kfree_skb(skb);
>
