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

[zhangsha.zhang]

From: Sha Zhang <zhangsha.zh...@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.zh...@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