netdev - [net 6/8] net/mlx5e: Fix memory usage issues in offloading TC flows

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Date:   Fri, 23 Mar 2018 15:05:32 -0700
From:   Saeed Mahameed <saeedm@...lanox.com>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, Jianbo Liu <jianbol@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>
Subject: [net 6/8] net/mlx5e: Fix memory usage issues in offloading TC flows

From: Jianbo Liu <jianbol@...lanox.com>

For NIC flows, the parsed attributes are not freed when we exit
successfully from mlx5e_configure_flower().

There is possible double free for eswitch flows. If error is returned
from rhashtable_insert_fast(), the parse attrs will be freed in
mlx5e_tc_del_flow(), but they will be freed again before exiting
mlx5e_configure_flower().

To fix both issues we do the following:
(1) change the condition that determines if to issue the free call to
    check if this flow is NIC flow, or it does not have encap action.
(2) reorder the code such that that the check and free calls are done
    before we attempt to add into the hash table.

Fixes: 232c001398ae ('net/mlx5e: Add support to neighbour update flow')
Signed-off-by: Jianbo Liu <jianbol@...lanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@...lanox.com>
Reviewed-by: Roi Dayan <roid@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index fa86a1466718..ae11678a31e8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -2608,19 +2608,19 @@ int mlx5e_configure_flower(struct mlx5e_priv *priv,
 	if (err != -EAGAIN)
 		flow->flags |= MLX5E_TC_FLOW_OFFLOADED;
 
+	if (!(flow->flags & MLX5E_TC_FLOW_ESWITCH) ||
+	    !(flow->esw_attr->action & MLX5_FLOW_CONTEXT_ACTION_ENCAP))
+		kvfree(parse_attr);
+
 	err = rhashtable_insert_fast(&tc->ht, &flow->node,
 				     tc->ht_params);
-	if (err)
-		goto err_del_rule;
+	if (err) {
+		mlx5e_tc_del_flow(priv, flow);
+		kfree(flow);
+	}
 
-	if (flow->flags & MLX5E_TC_FLOW_ESWITCH &&
-	    !(flow->esw_attr->action & MLX5_FLOW_CONTEXT_ACTION_ENCAP))
-		kvfree(parse_attr);
 	return err;
 
-err_del_rule:
-	mlx5e_tc_del_flow(priv, flow);
-
 err_free:
 	kvfree(parse_attr);
 	kfree(flow);
-- 
2.14.3