> From: dev <dev-boun...@dpdk.org> On Behalf Of bugzi...@dpdk.org
> Sent: Wednesday, May 26, 2021 9:24 AM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [Bug 721] Wrong event pointer in rx adapter
>
> https://bugs.dpdk.org/show_bug.cgi?id=721
>
> Bug ID: 721
> Summary: Wrong event pointer in rx adapter
> Product: DPDK
> Version: 20.11
> Hardware: All
> OS: All
> Status: UNCONFIRMED
> Severity: major
> Priority: Normal
> Component: eventdev
> Assignee: dev@dpdk.org
> Reporter: heng.w...@ericsson.com
> Target Milestone: ---
>
> Problem:
> In the function rxa_buffer_mbufs the ev is not reset to the array's first
> element before passing to a user call back function.
>
> Workaround:
> In the user callback, we must decrement ev by number of event before we can
> use
> it.
>
> Fix:
> I think we should pass &buf->events[buf->count] to dev_info->cb_fn instead of
> ev.
>
> 773 for (i = 0; i < num; i++) {
> 774 m = mbufs[i];
> 775
> 776 rss = do_rss ?
> 777 rxa_do_softrss(m, rx_adapter->rss_key_be) :
> 778 m->hash.rss;
> 779 ev->event = event;
> 780 ev->flow_id = (rss & ~flow_id_mask) |
> 781 (ev->flow_id & flow_id_mask);
> 782 ev->mbuf = m;
> 783 ev++;
> 784 }
> 785
> 786 if (dev_info->cb_fn) {
> 787
> 788 dropped = 0;
> 789 nb_cb = dev_info->cb_fn(eth_dev_id, rx_queue_id,
> 790 ETH_EVENT_BUFFER_SIZE,
> buf->count,
> ev,
> 791 num, dev_info->cb_arg, &dropped);
> 792 if (unlikely(nb_cb > num))
> 793 RTE_EDEV_LOG_ERR("Rx CB returned %d (> %d)
> events",
> 794 nb_cb, num);
> 795 else
> 796 num = nb_cb;
> 797 if (dropped)
> 798 rx_adapter->stats.rx_dropped += dropped;
> 799 }
+CC RX Adapter Maintainer, and Pavan as this code has been changed recently.
I've done a quick review of the above report, and believe it to be a genuine
bug,
however this code has been refactored in commit d7c428e557b as part of series
to " eventdev: support Rx adapter event vector".
The relevant diff here for reference:
Note "ev" pointer replaced with "&buf->events[buf->count]"
dropped = 0;
nb_cb = dev_info->cb_fn(eth_dev_id, rx_queue_id,
- ETH_EVENT_BUFFER_SIZE, buf->count, ev,
- num, dev_info->cb_arg, &dropped);
+ ETH_EVENT_BUFFER_SIZE, buf->count,
+ &buf->events[buf->count], num,
+ dev_info->cb_arg, &dropped);
if (unlikely(nb_cb > num))
Based on this investigation, although the code changed, the same bug seems
present,
as really &buf->events[0] should be passed to the callback?
Regards, -Harry
