netdev - [PATCH 2/3] net/mlx5e: Clean up error handling in mlx5e_alloc

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Date:   Sun, 27 Sep 2020 12:32:52 +0100
From:   Alex Dewar <alex.dewar90@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Dewar <alex.dewar90@...il.com>,
        Saeed Mahameed <saeedm@...dia.com>,
        Leon Romanovsky <leon@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] net/mlx5e: Clean up error handling in mlx5e_alloc_flow()

The variable flow is used after being allocated but before being
null-checked, which will cause a null pointer dereference if the
allocation failed. Fix this and tidy up the error-checking logic in this
function.

Addresses-Coverity: CID 1497154: Null pointer dereferences (REVERSE_INULL)
Signed-off-by: Alex Dewar <alex.dewar90@...il.com>
---
 .../net/ethernet/mellanox/mlx5/core/en_tc.c   | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index b3c57b984a2a..ed308407be6f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -4536,20 +4536,22 @@ mlx5e_alloc_flow(struct mlx5e_priv *priv, int attr_size,
 	struct mlx5e_tc_flow_parse_attr *parse_attr;
 	struct mlx5_flow_attr *attr;
 	struct mlx5e_tc_flow *flow;
-	int out_index, err;
+	int out_index;
 
 	flow = kzalloc(sizeof(*flow), GFP_KERNEL);
+	if (!flow)
+		return -ENOMEM;
 	parse_attr = kvzalloc(sizeof(*parse_attr), GFP_KERNEL);
+	if (!parse_attr)
+		goto err_free_flow;
 
 	flow->flags = flow_flags;
 	flow->cookie = f->cookie;
 	flow->priv = priv;
 
 	attr = mlx5_alloc_flow_attr(get_flow_name_space(flow));
-	if (!parse_attr || !flow || !attr) {
-		err = -ENOMEM;
-		goto err_free;
-	}
+	if (!attr)
+		goto err_free_parse_attr;
 	flow->attr = attr;
 
 	for (out_index = 0; out_index < MLX5_MAX_FLOW_FWD_VPORTS; out_index++)
@@ -4564,11 +4566,11 @@ mlx5e_alloc_flow(struct mlx5e_priv *priv, int attr_size,
 
 	return 0;
 
-err_free:
-	kfree(flow);
+err_free_parse_attr:
 	kvfree(parse_attr);
-	kfree(attr);
-	return err;
+err_free_flow:
+	kfree(flow);
+	return -ENOMEM;
 }
 
 static void
-- 
2.28.0