[dpdk-stable] [PATCH] vdpa/mlx5: fix configuration mutex cleanup

[Matan Azrad]

When the vDPA device is closed, the driver polling thread is canceled.
The polling thread locks the configuration mutex while it polls the CQs.

When the cancellation happens, it may terminate the thread inside the
critical section what remains the configuration mutex locked.

After device close, the driver may be configured again, in this case,
for example, when the first queue state is updated, the driver tries to
lock the mutex again and deadlock appears.

Initialize the mutex after the polling thread cancellation.

Fixes: 99abbd62c272 ("vdpa/mlx5: fix queue update synchronization")
Cc: stable at dpdk.org

Signed-off-by: Matan Azrad <matan at nvidia.com>
Acked-by: Xueming Li <xuemingl at nvidia.com>
---
 drivers/vdpa/mlx5/mlx5_vdpa.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vdpa/mlx5/mlx5_vdpa.c b/drivers/vdpa/mlx5/mlx5_vdpa.c
index b64f364..0b2f1ab 100644
--- a/drivers/vdpa/mlx5/mlx5_vdpa.c
+++ b/drivers/vdpa/mlx5/mlx5_vdpa.c
@@ -295,6 +295,8 @@
 	}
 	priv->configured = 0;
 	priv->vid = 0;
+	/* The mutex may stay locked after event thread cancel - initiate it. */
+	pthread_mutex_init(&priv->vq_config_lock, NULL);
 	DRV_LOG(INFO, "vDPA device %d was closed.", vid);
 	return ret;
 }
-- 
1.8.3.1