[PATCH 3/8] net/hns3: fix segmentfault for NEON and SVE

[Jie Hai]

From: Huisong Li <lihuisong at huawei.com>

Driver may fail to allocate bulk mbufs for Neon and SVE when rearm
mbuf. Currently, driver keeps going to handle packets even if there
isn't available descriptors to receive packets at this moment.
As a result, driver probably fills the mbufs with invalid data to
application and accesses to illegal address because of the VLD bit
of the descriptor at the "rx_rearm_start" position still being set.
So driver has to clear VLD bit for this descriptor in this scenario
in case of receiving packets later.

In addition, it is possible that the sum of the "rx_rearm_nb" and
"rx_rearm_start" is greater than total descriptor number of Rx queue
in the above scenario. So the index of rxq->sw_ring[] to set mbuf
pointer to NULL should also be fixed to avoid out-of-bounds memory
access.

Fixes: a3d4f4d291d7 ("net/hns3: support NEON Rx")
Fixes: f81a18f49152 ("net/hns3: fix mbuf leakage when RxQ started after reset")
Cc: stable at dpdk.org

Signed-off-by: Huisong Li <lihuisong at huawei.com>
---
 drivers/net/hns3/hns3_rxtx.c     | 2 +-
 drivers/net/hns3/hns3_rxtx_vec.h | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hns3/hns3_rxtx.c b/drivers/net/hns3/hns3_rxtx.c
index 13214d02d536..f28ca040be41 100644
--- a/drivers/net/hns3/hns3_rxtx.c
+++ b/drivers/net/hns3/hns3_rxtx.c
@@ -51,7 +51,7 @@ hns3_rx_queue_release_mbufs(struct hns3_rx_queue *rxq)
 			}
 		}
 		for (i = 0; i < rxq->rx_rearm_nb; i++)
-			rxq->sw_ring[rxq->rx_rearm_start + i].mbuf = NULL;
+			rxq->sw_ring[(rxq->rx_rearm_start + i) % rxq->nb_rx_desc].mbuf = NULL;
 	}
 
 	for (i = 0; i < rxq->bulk_mbuf_num; i++)
diff --git a/drivers/net/hns3/hns3_rxtx_vec.h b/drivers/net/hns3/hns3_rxtx_vec.h
index a9a6774294ef..9018e79c2f92 100644
--- a/drivers/net/hns3/hns3_rxtx_vec.h
+++ b/drivers/net/hns3/hns3_rxtx_vec.h
@@ -106,6 +106,11 @@ hns3_rxq_rearm_mbuf(struct hns3_rx_queue *rxq)
 
 	if (unlikely(rte_mempool_get_bulk(rxq->mb_pool, (void *)rxep,
 					  HNS3_DEFAULT_RXQ_REARM_THRESH) < 0)) {
+		/*
+		 * Clear VLD bit for the first descriptor rearmed in case
+		 * of going to receive packets later.
+		 */
+		rxdp[0].rx.bd_base_info = 0;
 		rte_eth_devices[rxq->port_id].data->rx_mbuf_alloc_failed++;
 		return;
 	}
-- 
2.30.0