[dpdk-dev] [PATCH] eventdev/rx_adapter: fix wrr buffer overrun issue

[Jayatheerthan, Jay]

Acked-by: Jay Jayatheerthan <jay.jayatheerthan at intel.com>

> -----Original Message-----
> From: Naga Harish K, S V <s.v.naga.harish.k at intel.com>
> Sent: Monday, October 18, 2021 1:56 PM
> To: jerinj at marvell.com; Jayatheerthan, Jay <jay.jayatheerthan at intel.com>
> Cc: dev at dpdk.org
> Subject: [PATCH] eventdev/rx_adapter: fix wrr buffer overrun issue
> 
> when a poll queue is removed from a rx_adapter instance, the wrr poll
> array is recomputed. The wrr array length is reduced in this case. The
> next wrr position to poll is stored in wrr_pos variable of rx_adapter
> instance. This wrr_pos can become invalid in some cases after wrr is
> recomputed. Using this variable to get the next queue and device pair
> may leed to wrr buffer overruns.
> 
> Resetting the wrr_pos to zero after recomputation of wrr array fixes
> the buffer overrun issue.
> 
> Fixes: 9c38b704d280 ("eventdev: add eth Rx adapter implementation")
> 
> Signed-off-by: Naga Harish K S V <s.v.naga.harish.k at intel.com>
> ---
>  lib/eventdev/rte_event_eth_rx_adapter.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/lib/eventdev/rte_event_eth_rx_adapter.c b/lib/eventdev/rte_event_eth_rx_adapter.c
> index bd68b8efe1..82a652d305 100644
> --- a/lib/eventdev/rte_event_eth_rx_adapter.c
> +++ b/lib/eventdev/rte_event_eth_rx_adapter.c
> @@ -2773,6 +2773,11 @@ rte_event_eth_rx_adapter_queue_del(uint8_t id, uint16_t eth_dev_id,
>  		rx_adapter->eth_rx_poll = rx_poll;
>  		rx_adapter->wrr_sched = rx_wrr;
>  		rx_adapter->wrr_len = nb_wrr;
> +		/*
> +		 * reset next poll start position (wrr_pos) to avoid buffer
> +		 * overrun when wrr_len is reduced in case of queue delete
> +		 */
> +		rx_adapter->wrr_pos = 0;
>  		rx_adapter->num_intr_vec += num_intr_vec;
> 
>  		if (dev_info->nb_dev_queues == 0) {
> --
> 2.25.1