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From: Qi Zhang <qi.z.zhang@intel.com>
To: beilei.xing@intel.com, wenzhuo.lu@intel.com,
	qiming.yang@intel.com, konstantin.ananyev@intel.com
Cc: dev@dpdk.org, Qi Zhang <qi.z.zhang@intel.com>, stable@dpdk.org
Subject: [dpdk-dev] [PATCH 3/3] net/ixgbe: fix invalid Tx threshold setup
Date: Sat,  4 May 2019 17:29:39 +0800	[thread overview]
Message-ID: <20190504092939.25326-4-qi.z.zhang@intel.com> (raw)
Message-ID: <20190504092939.HwI6_3PXcLLQ1wDgLlCyux5LJmhQIlpU7VAIOIpTafM@z> (raw)
In-Reply-To: <20190504092939.25326-1-qi.z.zhang@intel.com>

Tx desc's DD status is not cleaned by NIC automatically after packets
have been transmitted until software refill a new packet during next
loop. So when tx_free_thresh + tx_rs_thresh > nb_desc, it is possible
that an outdated DD status be checked as tx_next_dd, then segment fault
happen due to free a NULL mbuf pointer.

Then patch fixes this issue by
1. try to adapt tx_rs_thresh to an aggresive tx_free_thresh.
2. queue setup fail when tx_free_thresh + tx_rs_thresh > nb_desc

Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
---
 drivers/net/ixgbe/ixgbe_rxtx.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index 1fbc754ae..3072bc1b5 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -2496,14 +2496,29 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	 *  tx_rs_thresh must be a divisor of the ring size.
 	 *  tx_free_thresh must be greater than 0.
 	 *  tx_free_thresh must be less than the size of the ring minus 3.
+	 *  tx_free_thresh + tx_rs_thresh must not exceed nb_desc.
 	 * One descriptor in the TX ring is used as a sentinel to avoid a
 	 * H/W race condition, hence the maximum threshold constraints.
 	 * When set to zero use default values.
 	 */
-	tx_rs_thresh = (uint16_t)((tx_conf->tx_rs_thresh) ?
-			tx_conf->tx_rs_thresh : DEFAULT_TX_RS_THRESH);
 	tx_free_thresh = (uint16_t)((tx_conf->tx_free_thresh) ?
 			tx_conf->tx_free_thresh : DEFAULT_TX_FREE_THRESH);
+	/* force tx_rs_thresh to adapt an aggresive tx_free_thresh */
+	tx_rs_thresh = (DEFAULT_TX_RS_THRESH + tx_free_thresh > nb_desc) ?
+			nb_desc - tx_free_thresh : DEFAULT_TX_RS_THRESH;
+	if (tx_conf->tx_rs_thresh > 0)
+		tx_rs_thresh = tx_conf->tx_rs_thresh;
+	if (tx_rs_thresh + tx_free_thresh > nb_desc) {
+		PMD_INIT_LOG(ERR, "tx_rs_thresh + tx_free_thresh must not "
+			     "exceed nb_desc. (tx_rs_thresh=%u "
+			     "tx_free_thresh=%u nb_desc=%u port = %d queue=%d)",
+			     (unsigned int)tx_rs_thresh,
+			     (unsigned int)tx_free_thresh,
+			     (unsigned int)nb_desc,
+			     (int)dev->data->port_id,
+			     (int)queue_idx);
+		return -(EINVAL);
+	}
 	if (tx_rs_thresh >= (nb_desc - 2)) {
 		PMD_INIT_LOG(ERR, "tx_rs_thresh must be less than the number "
 			"of TX descriptors minus 2. (tx_rs_thresh=%u "
-- 
2.13.6


  parent reply	other threads:[~2019-05-04  9:28 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-04  9:29 [dpdk-dev] [PATCH 0/3] fix invalid Tx threshhold setup Qi Zhang
2019-05-04  9:29 ` Qi Zhang
2019-05-04  9:29 ` [dpdk-dev] [PATCH 1/3] net/i40e: fix invalid Tx threshold setup Qi Zhang
2019-05-04  9:29   ` Qi Zhang
2019-05-04  9:29 ` [dpdk-dev] [PATCH 2/3] net/ice: " Qi Zhang
2019-05-04  9:29   ` Qi Zhang
2019-05-04  9:29 ` Qi Zhang [this message]
2019-05-04  9:29   ` [dpdk-dev] [PATCH 3/3] net/ixgbe: " Qi Zhang
2019-05-15  6:36 ` [dpdk-dev] [PATCH 0/3] fix invalid Tx threshhold setup Xing, Beilei
2019-05-15  6:36   ` Xing, Beilei
2019-05-15  7:09   ` Zhang, Qi Z
2019-05-15  7:09     ` Zhang, Qi Z

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