netdev - [net 05/11] net/mlx5e: Hold reference on mirred devices while accessing them

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Date:   Thu,  2 Jul 2020 15:19:17 -0700
From:   Saeed Mahameed <saeedm@...lanox.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, Eli Cohen <eli@...lanox.com>,
        Vlad Buslov <vladbu@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>
Subject: [net 05/11] net/mlx5e: Hold reference on mirred devices while accessing them

From: Eli Cohen <eli@...lanox.com>

Net devices might be removed. For example, a vxlan device could be
deleted and its ifnidex would become invalid. Use dev_get_by_index()
instead of __dev_get_by_index() to hold reference on the device while
accessing it and release after done.

Fixes: 3c37745ec614 ("net/mlx5e: Properly deal with encap flows add/del under neigh update")
Signed-off-by: Eli Cohen <eli@...lanox.com>
Reviewed-by: Vlad Buslov <vladbu@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 75f169aef1cf..e88f98ab062f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1327,10 +1327,14 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
 			continue;
 
 		mirred_ifindex = parse_attr->mirred_ifindex[out_index];
-		out_dev = __dev_get_by_index(dev_net(priv->netdev),
-					     mirred_ifindex);
+		out_dev = dev_get_by_index(dev_net(priv->netdev),
+					   mirred_ifindex);
+		if (!out_dev)
+			return -ENODEV;
+
 		err = mlx5e_attach_encap(priv, flow, out_dev, out_index,
 					 extack, &encap_dev, &encap_valid);
+		dev_put(out_dev);
 		if (err)
 			return err;
 
-- 
2.26.2