[PATCH v2] vhost: fix avail idx update error when desc copy failed

[Gaoxiang Liu]

Hi, Chenbo
 Yes. It is the latest patch.



---- Replied Message ----
| From | Xia, Chenbo<chenbo.xia at intel.com> |
| Date | 06/23/2022 11:07 |
| To | Gaoxiang Liu<gaoxiangliu0 at 163.com>,
maxime.coquelin at redhat.com<maxime.coquelin at redhat.com> |
| Cc | dev at dpdk.org<dev at dpdk.org>,
liugaoxiang at huawei.com<liugaoxiang at huawei.com>,
stable at dpdk.org<stable at dpdk.org> |
| Subject | RE: [PATCH v2] vhost: fix avail idx update error when desc copy failed |
Hi Gaoxiang,

> -----Original Message-----
> From: Gaoxiang Liu <gaoxiangliu0 at 163.com>
> Sent: Wednesday, June 22, 2022 9:20 AM
> To: maxime.coquelin at redhat.com; Xia, Chenbo <chenbo.xia at intel.com>
> Cc: dev at dpdk.org; liugaoxiang at huawei.com; Gaoxiang Liu
> <gaoxiangliu0 at 163.com>; stable at dpdk.org
> Subject: [PATCH v2] vhost: fix avail idx update error when desc copy
> failed
>
> When copy_desc_to_mbuf function failed, i added 1.
> And last_avail_idx added i, other than i - 1.
> It may cause that the first mbuf in mbuf-list is dropped,
> the second mbuf in mbuf-list is received in the following
> rx procedure.
> And The pkt_len of the second mbuf is zero, resulting in
> segment fault when parsing the mbuf.

Guess this one is the latest? I believe something is wrong when you forward this,
it generates another patch because of your mail forwarding:

http://patchwork.dpdk.org/project/dpdk/list/?series=&submitter=&state=&q=&archive=&delegate=2642

/Chenbo

>
> Fixes: 0fd5608ef97f ("vhost: handle mbuf allocation failure")
> Cc: stable at dpdk.org
>
> Signed-off-by: Gaoxiang Liu <liugaoxiang at huawei.com>
>
> ---
> v2:
> * Fixed other idx update errors.
> ---
>  lib/vhost/virtio_net.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 68a26eb17d..eb254e1024 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -2850,11 +2850,11 @@ virtio_dev_tx_split(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>      if (dropped)
>          rte_pktmbuf_free_bulk(&pkts[i - 1], count - i + 1);
>
> -    vq->last_avail_idx += i;
> +    vq->last_avail_idx += i - dropped;
>
>      do_data_copy_dequeue(vq);
> -    if (unlikely(i < count))
> -        vq->shadow_used_idx = i;
> +    if (unlikely((i - dropped) < count))
> +        vq->shadow_used_idx = i - dropped;
>      if (likely(vq->shadow_used_idx)) {
>          flush_shadow_used_ring_split(dev, vq);
>          vhost_vring_call_split(dev, vq);
> --
> 2.32.0
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