Re: [PATCH v2] examples/eventdev: fix segment fault with generic pipeline

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, Sep 18, 2024 at 12:10 PM Chengwen Feng <fengchengwen@huawei.com> wrote:
>
> There was a segmentation fault when executing eventdev_pipeline with
> command [1] with ConnectX-5 NIC card:
>
> 0x000000000079208c in rte_eth_tx_buffer (tx_pkt=0x16f8ed300, buffer=0x100,
>                    queue_id=11, port_id=0) at
>                    ../lib/ethdev/rte_ethdev.h:6636
> txa_service_tx (txa=0x17b19d080, ev=0xffffffffe500, n=4) at
>                    ../lib/eventdev/rte_event_eth_tx_adapter.c:631
> 0x0000000000792234 in txa_service_func (args=0x17b19d080) at
>                    ../lib/eventdev/rte_event_eth_tx_adapter.c:666
> 0x00000000008b0784 in service_runner_do_callback (s=0x17fffe100,
>                    cs=0x17ffb5f80, service_idx=2) at
>                    ../lib/eal/common/rte_service.c:405
> 0x00000000008b0ad8 in service_run (i=2, cs=0x17ffb5f80,
>                    service_mask=18446744073709551615, s=0x17fffe100,
>                    serialize_mt_unsafe=0) at
>                    ../lib/eal/common/rte_service.c:441
> 0x00000000008b0c68 in rte_service_run_iter_on_app_lcore (id=2,
>                    serialize_mt_unsafe=0) at
>                    ../lib/eal/common/rte_service.c:477
> 0x000000000057bcc4 in schedule_devices (lcore_id=0) at
>                    ../examples/eventdev_pipeline/pipeline_common.h:138
> 0x000000000057ca94 in worker_generic_burst (arg=0x17b131e80) at
>                    ../examples/eventdev_pipeline/
>                    pipeline_worker_generic.c:83
> 0x00000000005794a8 in main (argc=11, argv=0xfffffffff470) at
>                    ../examples/eventdev_pipeline/main.c:449
>
> The root cause is that the queue_id (11) is invalid, the queue_id comes
> from mbuf.hash.txadapter.txq which may pre-write by NIC driver when
> receiving packets (e.g. pre-write mbuf.hash.fdir.hi field).
>
> Because this example only enabled one ethdev queue, so fixes it by reset
> txq to zero in the first worker stage.
>
> [1] dpdk-eventdev_pipeline -l 0-48 --vdev event_sw0 -- -r1 -t1 -e1 -w ff0
>     -s5 -n0 -c32 -W1000 -D
> When launch eventdev_pipeline with command [1],  event_sw
>
> Fixes: 81fb40f95c82 ("examples/eventdev: add generic worker pipeline")
> Cc: stable@dpdk.org
>
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> Signed-off-by: Chenxingyu Wang <wangchenxingyu@huawei.com>
> Acked-by: Pavan Nikhilesh <pbhagavatula@marvell.com>


Applied to dpdk-next-eventdev/for-main. Thanks


>
> ---
> v2: fix check patch and git log issues.
>
> ---
>  .mailmap                                             |  1 +
>  examples/eventdev_pipeline/pipeline_worker_generic.c | 12 ++++++++----
>  2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/.mailmap b/.mailmap
> index 4a508bafad..cee686e029 100644
> --- a/.mailmap
> +++ b/.mailmap
> @@ -236,6 +236,7 @@ Cheng Peng <cheng.peng5@zte.com.cn>
>  Chengwen Feng <fengchengwen@huawei.com>
>  Chenmin Sun <chenmin.sun@intel.com>
>  Chenming Chang <ccm@ccm.ink>
> +Chenxingyu Wang <wangchenxingyu@huawei.com>
>  Chenxu Di <chenxux.di@intel.com>
>  Chenyu Huang <chenyux.huang@intel.com>
>  Cheryl Houser <chouser@vmware.com>
> diff --git a/examples/eventdev_pipeline/pipeline_worker_generic.c b/examples/eventdev_pipeline/pipeline_worker_generic.c
> index 783f68c91e..831d7fd53d 100644
> --- a/examples/eventdev_pipeline/pipeline_worker_generic.c
> +++ b/examples/eventdev_pipeline/pipeline_worker_generic.c
> @@ -38,10 +38,12 @@ worker_generic(void *arg)
>                 }
>                 received++;
>
> -               /* The first worker stage does classification */
> -               if (ev.queue_id == cdata.qid[0])
> +               /* The first worker stage does classification and sets txq. */
> +               if (ev.queue_id == cdata.qid[0]) {
>                         ev.flow_id = ev.mbuf->hash.rss
>                                                 % cdata.num_fids;
> +                       rte_event_eth_tx_adapter_txq_set(ev.mbuf, 0);
> +               }
>
>                 ev.queue_id = cdata.next_qid[ev.queue_id];
>                 ev.op = RTE_EVENT_OP_FORWARD;
> @@ -96,10 +98,12 @@ worker_generic_burst(void *arg)
>
>                 for (i = 0; i < nb_rx; i++) {
>
> -                       /* The first worker stage does classification */
> -                       if (events[i].queue_id == cdata.qid[0])
> +                       /* The first worker stage does classification and sets txq. */
> +                       if (events[i].queue_id == cdata.qid[0]) {
>                                 events[i].flow_id = events[i].mbuf->hash.rss
>                                                         % cdata.num_fids;
> +                               rte_event_eth_tx_adapter_txq_set(events[i].mbuf, 0);
> +                       }
>
>                         events[i].queue_id = cdata.next_qid[events[i].queue_id];
>                         events[i].op = RTE_EVENT_OP_FORWARD;
> --
> 2.17.1
>