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

[Jerin Jacob <jerinjacobk@gmail.com>]

On Mon, Oct 18, 2021 at 4:39 PM Jayatheerthan, Jay
<jay.jayatheerthan@intel.com> wrote:
>
> Acked-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>


Changed the subject to:
eventdev/rx_adapter: fix WRR buffer overrun issue
Cced stable@dpdk.org

Series applied to dpdk-next-net-eventdev/for-main. Thanks

>
> > -----Original Message-----
> > From: Naga Harish K, S V <s.v.naga.harish.k@intel.com>
> > Sent: Monday, October 18, 2021 1:56 PM
> > To: jerinj@marvell.com; Jayatheerthan, Jay <jay.jayatheerthan@intel.com>
> > Cc: dev@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@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
>