net/cxgbe: fix crash when accessing empty Tx mbuf list

Ensure packets are available before accessing the mbuf list in Tx
burst function. Otherwise, just reclaim completed Tx descriptors and
exit.

Fixes: b1df19e43e1d ("net/cxgbe: fix prefetch for non-coalesced Tx packets")
Cc: stable@dpdk.org
Reported-by: Brian Poole <brian90013@gmail.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>

diff --git a/drivers/net/cxgbe/cxgbe_ethdev.c b/drivers/net/cxgbe/cxgbe_ethdev.c
index 7c6016d..1205e17 100644 (file)
--- a/drivers/net/cxgbe/cxgbe_ethdev.c
+++ b/drivers/net/cxgbe/cxgbe_ethdev.c
@@ -71,6 +71,9 @@ uint16_t cxgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
        t4_os_lock(&txq->txq_lock);
        /* free up desc from already completed tx */
        reclaim_completed_tx(&txq->q);
+       if (unlikely(!nb_pkts))
+               goto out_unlock;
+
        rte_prefetch0(rte_pktmbuf_mtod(tx_pkts[0], volatile void *));
        while (total_sent < nb_pkts) {
                pkts_remain = nb_pkts - total_sent;
@@ -91,6 +94,7 @@ uint16_t cxgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
                reclaim_completed_tx(&txq->q);
        }
 
+out_unlock:
        t4_os_unlock(&txq->txq_lock);
        return total_sent;
 }