diff mbox

[dpdk-dev] net/mlx5: fix deadlock of link status alarm

Message ID 20180109090920.14033-1-yskoh@mellanox.com (mailing list archive)
State Superseded, archived
Delegated to: Shahaf Shuler
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Yongseok Koh Jan. 9, 2018, 9:09 a.m. UTC 
  If mlx5_dev_link_status_handler() is executed while canceling the alarm,
deadlock can happen because rte_eal_alarm_cancel() waits for all callbackes
to finish execution and both calls are protected by priv->lock.

Fixes: 198a3c339a8f ("mlx5: handle link status interrupts")
Cc: stable@dpdk.org

Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
---
 drivers/net/mlx5/mlx5.h        | 16 ++++++++++++++++
 drivers/net/mlx5/mlx5_ethdev.c | 13 +++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

Comments

Nélio Laranjeiro Jan. 10, 2018, 10:11 a.m. UTC | #1 
On Tue, Jan 09, 2018 at 01:09:20AM -0800, Yongseok Koh wrote:
> If mlx5_dev_link_status_handler() is executed while canceling the alarm,
> deadlock can happen because rte_eal_alarm_cancel() waits for all callbackes
> to finish execution and both calls are protected by priv->lock.
> 
> Fixes: 198a3c339a8f ("mlx5: handle link status interrupts")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
<snip/>

Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

Thanks,
diff mbox

Patch

diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index e6a69b823..1a4f444c7 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -165,6 +165,22 @@  priv_lock(struct priv *priv)
 }
 
 /**
+ * Try to lock private structure to protect it from concurrent access in the
+ * control path.
+ *
+ * @param priv
+ *   Pointer to private structure.
+ *
+ * @return
+ *   1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline int
+priv_trylock(struct priv *priv)
+{
+	return rte_spinlock_trylock(&priv->lock);
+}
+
+/**
  * Unlock private structure.
  *
  * @param priv
diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index 282ef241e..9354dd17f 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -1185,8 +1185,12 @@  mlx5_dev_link_status_handler(void *arg)
 	struct priv *priv = dev->data->dev_private;
 	int ret;
 
-	priv_lock(priv);
-	assert(priv->pending_alarm == 1);
+	while (!priv_trylock(priv)) {
+		/* Alarm is being canceled. */
+		if (priv->pending_alarm == 0)
+			return;
+		rte_pause();
+	}
 	priv->pending_alarm = 0;
 	ret = priv_link_status_update(priv);
 	priv_unlock(priv);
@@ -1256,9 +1260,10 @@  priv_dev_interrupt_handler_uninstall(struct priv *priv, struct rte_eth_dev *dev)
 	if (priv->primary_socket)
 		rte_intr_callback_unregister(&priv->intr_handle_socket,
 					     mlx5_dev_handler_socket, dev);
-	if (priv->pending_alarm)
+	if (priv->pending_alarm) {
+		priv->pending_alarm = 0;
 		rte_eal_alarm_cancel(mlx5_dev_link_status_handler, dev);
-	priv->pending_alarm = 0;
+	}
 	priv->intr_handle.fd = 0;
 	priv->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN;
 	priv->intr_handle_socket.fd = 0;