From: "Björn Töpel" <bjorn.topel@gmail.com>
To: Ilya Maximets <i.maximets@samsung.com>
Cc: Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
Xdp <xdp-newbies@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"Jonathan Lemon" <jonathan.lemon@gmail.com>,
"Jakub Kicinski" <jakub.kicinski@netronome.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>
Subject: Re: [PATCH bpf] xdp: fix possible cq entry leak
Date: Fri, 5 Jul 2019 08:42:56 +0200 [thread overview]
Message-ID: <CAJ+HfNi2EdLwtq9SfccZBymDMv_cW5+vxB-JLqxyvYS_TG3ScA@mail.gmail.com> (raw)
In-Reply-To: <20190704142503.23501-1-i.maximets@samsung.com>
On Thu, 4 Jul 2019 at 16:25, Ilya Maximets <i.maximets@samsung.com> wrote:
>
> Completion queue address reservation could not be undone.
> In case of bad 'queue_id' or skb allocation failure, reserved entry
> will be leaked reducing the total capacity of completion queue.
>
> Fix that by moving reservation to the point where failure is not
> possible. Additionally, 'queue_id' checking moved out from the loop
> since there is no point to check it there.
>
Good catch, Ilya! Thanks for the patch!
Acked-by: Björn Töpel <bjorn.topel@intel.com>
> Fixes: 35fcde7f8deb ("xsk: support for Tx")
> Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
> ---
> net/xdp/xsk.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index f53a6ef7c155..703cf5ea448b 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -226,6 +226,9 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
>
> mutex_lock(&xs->mutex);
>
> + if (xs->queue_id >= xs->dev->real_num_tx_queues)
> + goto out;
> +
> while (xskq_peek_desc(xs->tx, &desc)) {
> char *buffer;
> u64 addr;
> @@ -236,12 +239,6 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
> goto out;
> }
>
> - if (xskq_reserve_addr(xs->umem->cq))
> - goto out;
> -
> - if (xs->queue_id >= xs->dev->real_num_tx_queues)
> - goto out;
> -
> len = desc.len;
> skb = sock_alloc_send_skb(sk, len, 1, &err);
> if (unlikely(!skb)) {
> @@ -253,7 +250,7 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
> addr = desc.addr;
> buffer = xdp_umem_get_data(xs->umem, addr);
> err = skb_store_bits(skb, 0, buffer, len);
> - if (unlikely(err)) {
> + if (unlikely(err) || xskq_reserve_addr(xs->umem->cq)) {
> kfree_skb(skb);
> goto out;
> }
> --
> 2.17.1
>
next prev parent reply other threads:[~2019-07-05 6:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190704142509eucas1p268eb9ca87bcc0bffb60891f88f3f6642@eucas1p2.samsung.com>
2019-07-04 14:25 ` [PATCH bpf] xdp: fix possible cq entry leak Ilya Maximets
2019-07-05 6:42 ` Björn Töpel [this message]
2019-07-08 21:25 ` William Tu
2019-07-12 13:07 ` Daniel Borkmann
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