[dpdk-dev] [PATCH] net/mlx4: fix buffer leakage on device close

[Viacheslav Ovsiienko]

The mlx4 PMD tracks the buffers (mbufs) for the packets being
transmitted in the dedicated array named as "elts". The tx_burst
routine frees the mbufs from this array once it needs to rearm
the hardware descriptor and store the new mbuf, so it looks
like as replacement mbuf pointer in the elts array.

On the device stop mlx4 PMD freed only the part of elts according
tail and head pointers, leaking the rest of buffers, remained in
the elts array.

Fixes: a2ce2121c01c ("net/mlx4: separate Tx configuration functions")
Cc: stable at dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/net/mlx4/mlx4_rxtx.c |  4 ----
 drivers/net/mlx4/mlx4_txq.c  | 19 +++++++++----------
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/net/mlx4/mlx4_rxtx.c b/drivers/net/mlx4/mlx4_rxtx.c
index adc1c9bf81..ecf08f53cf 100644
--- a/drivers/net/mlx4/mlx4_rxtx.c
+++ b/drivers/net/mlx4/mlx4_rxtx.c
@@ -921,10 +921,6 @@ mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 		if (likely(elt->buf != NULL)) {
 			struct rte_mbuf *tmp = elt->buf;
 
-#ifdef RTE_LIBRTE_MLX4_DEBUG
-			/* Poisoning. */
-			memset(&elt->buf, 0x66, sizeof(struct rte_mbuf *));
-#endif
 			/* Faster than rte_pktmbuf_free(). */
 			do {
 				struct rte_mbuf *next = tmp->next;
diff --git a/drivers/net/mlx4/mlx4_txq.c b/drivers/net/mlx4/mlx4_txq.c
index 31ab308050..2df26842fb 100644
--- a/drivers/net/mlx4/mlx4_txq.c
+++ b/drivers/net/mlx4/mlx4_txq.c
@@ -206,19 +206,18 @@ mlx4_tx_uar_uninit_secondary(struct rte_eth_dev *dev __rte_unused)
 static void
 mlx4_txq_free_elts(struct txq *txq)
 {
-	unsigned int elts_head = txq->elts_head;
-	unsigned int elts_tail = txq->elts_tail;
 	struct txq_elt (*elts)[txq->elts_n] = txq->elts;
-	unsigned int elts_m = txq->elts_n - 1;
+	unsigned int n = txq->elts_n;
 
-	DEBUG("%p: freeing WRs", (void *)txq);
-	while (elts_tail != elts_head) {
-		struct txq_elt *elt = &(*elts)[elts_tail++ & elts_m];
+	DEBUG("%p: freeing WRs, %u", (void *)txq, n);
+	while (n--) {
+		struct txq_elt *elt = &(*elts)[n];
 
-		MLX4_ASSERT(elt->buf != NULL);
-		rte_pktmbuf_free(elt->buf);
-		elt->buf = NULL;
-		elt->wqe = NULL;
+		if (elt->buf) {
+			rte_pktmbuf_free(elt->buf);
+			elt->buf = NULL;
+			elt->wqe = NULL;
+		}
 	}
 	txq->elts_tail = txq->elts_head;
 }
-- 
2.18.1