[dpdk-dev] [PATCH v3] bonding: fix the segfault caused by the race condition between master thread and eal-intr-thread

[<zhangsha.zhang@huawei.com>]

From: Sha Zhang <zhangsha.zhang@huawei.com>

Function slave_configure calls functions bond_ethdev_lsc_event_callback and
slave_eth_dev->dev_ops->link_update to fix updating slave link status.
But there is a low probability that process may be crashed if the master
thread, which create bonding-device, adds the active_slave_count of the
bond to nozero while the rx_ring or tx_ring of it haven't been created.

This patch moves the functions bond_ethdev_lsc_event_callback and
slave_eth_dev->dev_ops->link_update to eal-intr-thread to aviod the
competition.

Fixes: 210903803f6e ("net/bonding: fix updating slave link status")

Signed-off-by: Sha Zhang <zhangsha.zhang@huawei.com>
---
 drivers/net/bonding/rte_eth_bond_pmd.c | 58 +++++++++++++++++++++++++++++-----
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c b/drivers/net/bonding/rte_eth_bond_pmd.c
index 383e27c..bc0ee7f 100644
--- a/drivers/net/bonding/rte_eth_bond_pmd.c
+++ b/drivers/net/bonding/rte_eth_bond_pmd.c
@@ -53,6 +53,7 @@
 
 #define REORDER_PERIOD_MS 10
 #define DEFAULT_POLLING_INTERVAL_10_MS (10)
+#define BOND_LSC_DELAY_TIME_US (10 * 1000)
 
 #define HASH_L4_PORTS(h) ((h)->src_port ^ (h)->dst_port)
 
@@ -1800,14 +1801,6 @@ struct bwg_slave {
 		}
 	}
 
-	/* If lsc interrupt is set, check initial slave's link status */
-	if (slave_eth_dev->data->dev_flags & RTE_ETH_DEV_INTR_LSC) {
-		slave_eth_dev->dev_ops->link_update(slave_eth_dev, 0);
-		bond_ethdev_lsc_event_callback(slave_eth_dev->data->port_id,
-			RTE_ETH_EVENT_INTR_LSC, &bonded_eth_dev->data->port_id,
-			NULL);
-	}
-
 	return 0;
 }
 
@@ -1878,6 +1871,51 @@ struct bwg_slave {
 static void
 bond_ethdev_promiscuous_enable(struct rte_eth_dev *eth_dev);
 
+static void
+bond_ethdev_slave_lsc_delay(void *cb_arg)
+{
+	struct rte_eth_dev *bonded_ethdev, *slave_dev;
+	struct bond_dev_private *internals;
+
+	/* Default value for polling slave found is true as we don't
+	 *  want todisable the polling thread if we cannot get the lock.
+	 */
+	int i = 0;
+
+	if (!cb_arg)
+		return;
+
+	bonded_ethdev = (struct rte_eth_dev *)cb_arg;
+	if (!bonded_ethdev->data->dev_started)
+		return;
+
+	internals = (struct bond_dev_private *)bonded_ethdev->data->dev_private;
+	if (!rte_spinlock_trylock(&internals->lock)) {
+		rte_eal_alarm_set(BOND_LSC_DELAY_TIME_US * 10,
+				  bond_ethdev_slave_lsc_delay,
+				  (void *)&rte_eth_devices[internals->port_id]);
+		return;
+	}
+
+	for (i = 0; i < internals->slave_count; i++) {
+		slave_dev = &(rte_eth_devices[internals->slaves[i].port_id]);
+		if (slave_dev->data->dev_conf.intr_conf.lsc != 0) {
+			if (slave_dev->dev_ops &&
+			    slave_dev->dev_ops->link_update)
+				slave_dev->dev_ops->link_update(slave_dev, 0);
+			bond_ethdev_lsc_event_callback(
+				internals->slaves[i].port_id,
+				RTE_ETH_EVENT_INTR_LSC,
+				&bonded_ethdev->data->port_id, NULL);
+		}
+	}
+	rte_spinlock_unlock(&internals->lock);
+	RTE_LOG(INFO, EAL,
+		"bond %s(%u): slave num %d, current active slave num %d\n",
+		bonded_ethdev->data->name, bonded_ethdev->data->port_id,
+		internals->slave_count, internals->active_slave_count);
+}
+
 static int
 bond_ethdev_start(struct rte_eth_dev *eth_dev)
 {
@@ -1953,6 +1991,10 @@ struct bwg_slave {
 		if (internals->slaves[i].link_status_poll_enabled)
 			internals->link_status_polling_enabled = 1;
 	}
+
+	rte_eal_alarm_set(BOND_LSC_DELAY_TIME_US, bond_ethdev_slave_lsc_delay,
+			  (void *)&rte_eth_devices[internals->port_id]);
+
 	/* start polling if needed */
 	if (internals->link_status_polling_enabled) {
 		rte_eal_alarm_set(
-- 
1.8.3.1