From: John Fastabend <john.fastabend@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>,
Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
netdev@vger.kernel.org,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Saeed Mahameed <saeedm@mellanox.com>,
Daniel Borkmann <borkmann@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
Tariq Toukan <tariqt@mellanox.com>
Subject: Re: [net PATCH 3/4] virtio_net: fix memory leak in XDP_REDIRECT
Date: Tue, 20 Feb 2018 08:59:45 -0800 [thread overview]
Message-ID: <2dd5f441-d6e7-368c-743f-af8f720685f8@gmail.com> (raw)
In-Reply-To: <151913353504.28247.963049986131113639.stgit@firesoul>
On 02/20/2018 05:32 AM, Jesper Dangaard Brouer wrote:
> XDP_REDIRECT calling xdp_do_redirect() can fail for multiple reasons
> (which can be inspected by tracepoints). The current semantics is that
> on failure the driver calling xdp_do_redirect() must handle freeing or
> recycling the page associated with this frame. This can be seen as an
> optimization, as drivers usually have an optimized XDP_DROP code path
> for frame recycling in place already.
>
> The virtio_net driver didn't handle when xdp_do_redirect() failed.
> This caused a memory leak as the page refcnt wasn't decremented on
> failures.
>
> The function __virtnet_xdp_xmit() did handle one type of failure,
> when the xmit queue virtqueue_add_outbuf() is full, which "hides"
> releasing a refcnt on the page. Instead the function __virtnet_xdp_xmit()
> must follow API of xdp_do_redirect(), which on errors leave it up to
> the caller to free the page, of the failed send operation.
>
> Fixes: 186b3c998c50 ("virtio-net: support XDP_REDIRECT")
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---
Acked-by: John Fastabend <john.fastabend@gmail.com>
next prev parent reply other threads:[~2018-02-20 16:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-20 13:31 [net PATCH 0/4] virtio_net: several bugs in XDP code for driver virtio_net Jesper Dangaard Brouer
2018-02-20 13:32 ` [net PATCH 1/4] virtio_net: disable XDP_REDIRECT in receive_mergeable() case Jesper Dangaard Brouer
2018-02-20 16:56 ` John Fastabend
2018-02-27 0:40 ` Michael S. Tsirkin
2018-02-27 2:25 ` Jason Wang
2018-02-27 2:28 ` Jason Wang
2018-02-20 13:32 ` [net PATCH 2/4] virtio_net: fix XDP code path in receive_small() Jesper Dangaard Brouer
2018-02-20 16:57 ` John Fastabend
2018-02-20 13:32 ` [net PATCH 3/4] virtio_net: fix memory leak in XDP_REDIRECT Jesper Dangaard Brouer
2018-02-20 16:59 ` John Fastabend [this message]
2018-02-20 13:32 ` [net PATCH 4/4] virtio_net: fix ndo_xdp_xmit crash towards dev not ready for XDP Jesper Dangaard Brouer
2018-02-20 17:01 ` John Fastabend
2018-02-21 20:09 ` [net PATCH 0/4] virtio_net: several bugs in XDP code for driver virtio_net David Miller
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