From: Petr Machata <pe...@mellanox.com>
Date: Tue, 20 Nov 2018 11:39:56 +0000
> When a packet is trapped and the corresponding SKB marked as
> already-forwarded, it retains this marking even after it is forwarded
> across veth links into another bridge. There, since it ingresses the
> bridge over veth, which doesn't have offload_fwd_mark, it triggers a
> warning in nbp_switchdev_frame_mark().
>
> Then nbp_switchdev_allowed_egress() decides not to allow egress from
> this bridge through another veth, because the SKB is already marked, and
> the mark (of 0) of course matches. Thus the packet is incorrectly
> blocked.
>
> Solve by resetting offload_fwd_mark() in skb_scrub_packet(). That
> function is called from tunnels and also from veth, and thus catches the
> cases where traffic is forwarded between bridges and transformed in a
> way that invalidates the marking.
>
> Fixes: 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for stacked
> devices")
> Fixes: abf4bb6b63d0 ("skbuff: Add the offload_mr_fwd_mark field")
> Signed-off-by: Petr Machata <pe...@mellanox.com>
> Suggested-by: Ido Schimmel <ido...@mellanox.com>
Applied and queued up for -stable, thanks.
