Re: [dpdk-dev] [PATCH v1] vhost: add sanity check for resubmiting reqs in split ring

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Hi Li,

Adding Jin Yu who introduced this function.

On 8/27/21 07:12, Li Feng wrote:
> When getting reqs from the avail ring, the id may exceed inflight
> queue size. Then the dpdk will crash forever.

You need to add Fixes tag and Cc stable@dpdk.org so that it can be
backported.

> Signed-off-by: Li Feng <fengli@smartx.com>
> ---
>   lib/vhost/vhost_user.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index 29a4c9af60..f09d0f6a48 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -1823,8 +1823,14 @@ vhost_check_queue_inflights_split(struct virtio_net *dev,
>   	last_io = inflight_split->last_inflight_io;
>   
>   	if (inflight_split->used_idx != used->idx) {
> -		inflight_split->desc[last_io].inflight = 0;
> -		rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
> +		if (unlikely(last_io >= inflight_split->desc_num)) {
> +			VHOST_LOG_CONFIG(ERR, "last_inflight_io '%"PRIu16"' exceeds inflight "
> +				"queue size (%"PRIu16").\n", last_io,
> +				inflight_split->desc_num);

If such error happens, shouldn't we return RTE_VHOST_MSG_RESULT_ERR
instead of just logging an error?

> +		} else {
> +			inflight_split->desc[last_io].inflight = 0;
> +			rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
> +		}
>   		inflight_split->used_idx = used->idx;
>   	}
>   
> 

Regards,
Maxime