[PATCH v3 50/51] net/sxe2: restore NULL check in vectorized Tx mbuf release

[liujie5 at linkdatatechnology.com]

From: Jie Liu <liujie5 at linkdatatechnology.com>

sxe2_tx_queue_mbufs_release_vec() calls rte_pktmbuf_free_seg() on each
buffer entry without checking for NULL. rte_pktmbuf_free_seg() does not
tolerate NULL and dereferences its argument, so a stop/start cycle or
any unwritten slot in the release range can crash.

Restore the NULL check before freeing each mbuf.

Cc: stable at dpdk.org
Cc: stephen at networkplumber.org
Signed-off-by: Jie Liu <liujie5 at linkdatatechnology.com>
---
 drivers/net/sxe2/sxe2_txrx_vec.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/sxe2/sxe2_txrx_vec.c b/drivers/net/sxe2/sxe2_txrx_vec.c
index 05940c8cb5..7c5da33dd5 100644
--- a/drivers/net/sxe2/sxe2_txrx_vec.c
+++ b/drivers/net/sxe2/sxe2_txrx_vec.c
@@ -183,15 +183,19 @@ static void sxe2_tx_queue_mbufs_release_vec(struct sxe2_tx_queue *txq)
 
 	if (txq->next_use < i) {
 		for ( ; i < txq->ring_depth; ++i) {
-			rte_pktmbuf_free_seg(buffer_vec[i].mbuf);
-			buffer_vec[i].mbuf = NULL;
+			if (buffer_vec[i].mbuf != NULL) {
+				rte_pktmbuf_free_seg(buffer_vec[i].mbuf);
+				buffer_vec[i].mbuf = NULL;
+			}
 		}
 		i = 0;
 	}
 
 	for ( ; i < txq->next_use; ++i) {
-		rte_pktmbuf_free_seg(buffer_vec[i].mbuf);
-		buffer_vec[i].mbuf = NULL;
+		if (buffer_vec[i].mbuf != NULL) {
+			rte_pktmbuf_free_seg(buffer_vec[i].mbuf);
+			buffer_vec[i].mbuf = NULL;
+		}
 	}
 }
 
-- 
2.52.0