Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 31 Mar 2023 21:25:14 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Felix =?UTF-8?B?SMO8dHRuZXI=?= <felix.huettner@mail.schwarz>
Cc:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "dev@openvswitch.org" <dev@openvswitch.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Luca Czesla <Luca.Czesla@mail.schwarz>
Subject: Re: [PATCH] net: openvswitch: fix race on port output
Message-ID: <20230331212514.7a9ee3d9@kernel.org>
In-Reply-To: <DU0PR10MB5244A38E7712028763169A93EA8F9@DU0PR10MB5244.EURPRD10.PROD.OUTLOOK.COM>
References: <DU0PR10MB5244A38E7712028763169A93EA8F9@DU0PR10MB5244.EURPRD10.PROD.OUTLOOK.COM>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, 31 Mar 2023 06:25:13 +0000 Felix H=C3=BCttner wrote:
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 253584777101..6628323b7bea 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -3199,6 +3199,7 @@ static u16 skb_tx_hash(const struct net_device *dev,
>         }
>=20
>         if (skb_rx_queue_recorded(skb)) {
> +               BUG_ON(unlikely(qcount =3D=3D 0));

DEBUG_NET_WARN_ON()

>                 hash =3D skb_get_rx_queue(skb);
>                 if (hash >=3D qoffset)
>                         hash -=3D qoffset;
> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
> index ca3ebfdb3023..33b317e5f9a5 100644
> --- a/net/openvswitch/actions.c
> +++ b/net/openvswitch/actions.c
> @@ -913,7 +913,7 @@ static void do_output(struct datapath *dp, struct sk_=
buff *skb, int out_port,
>  {
>         struct vport *vport =3D ovs_vport_rcu(dp, out_port);
>=20
> -       if (likely(vport)) {
> +       if (likely(vport && vport->dev->reg_state =3D=3D NETREG_REGISTERE=
D)) {

Without looking too closely netif_carrier_ok() seems like a more
appropriate check for liveness on the datapath?

>                 u16 mru =3D OVS_CB(skb)->mru;
>                 u32 cutlen =3D OVS_CB(skb)->cutlen;
>=20
> --
> 2.40.0
>=20
> Diese E Mail enth=C3=A4lt m=C3=B6glicherweise vertrauliche Inhalte und is=
t nur f=C3=BCr die Verwertung durch den vorgesehenen Empf=C3=A4nger bestimm=
t. Sollten Sie nicht der vorgesehene Empf=C3=A4nger sein, setzen Sie den Ab=
sender bitte unverz=C3=BCglich in Kenntnis und l=C3=B6schen diese E Mail. H=
inweise zum Datenschutz finden Sie hier<https://www.datenschutz.schwarz>.

You gotta get rid of this to work upstream.