[PATCH] [v2] net/mlx5e: fix a double-free in arfs_create_groups

[Zhipeng Lu]

When `in` allocated by kvzalloc fails, arfs_create_groups will free
ft->g and return an error. However, arfs_create_table, the only caller of
arfs_create_groups, will hold this error and call to
mlx5e_destroy_flow_table, in which the ft->g will be freed again.

Fixes: 1cabe6b0965e ("net/mlx5e: Create aRFS flow tables")
Signed-off-by: Zhipeng Lu <alexious@xxxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
---
Changelog:

v2: free ft->g just in arfs_create_groups with a unwind ladde.
---
 .../net/ethernet/mellanox/mlx5/core/en_arfs.c   | 17 +++++++++--------
 drivers/net/ethernet/mellanox/mlx5/core/en_fs.c |  1 -
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c
index bb7f86c993e5..c96f4c571b63 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c
@@ -252,13 +252,14 @@ static int arfs_create_groups(struct mlx5e_flow_table *ft,
 	int err;
 	u8 *mc;
 
+	ft->num_groups = 0;
+
 	ft->g = kcalloc(MLX5E_ARFS_NUM_GROUPS,
 			sizeof(*ft->g), GFP_KERNEL);
 	in = kvzalloc(inlen, GFP_KERNEL);
 	if  (!in || !ft->g) {
-		kfree(ft->g);
-		kvfree(in);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto free_ft;
 	}
 
 	mc = MLX5_ADDR_OF(create_flow_group_in, in, match_criteria);
@@ -278,7 +279,7 @@ static int arfs_create_groups(struct mlx5e_flow_table *ft,
 		break;
 	default:
 		err = -EINVAL;
-		goto out;
+		goto free_ft;
 	}
 
 	switch (type) {
@@ -300,7 +301,7 @@ static int arfs_create_groups(struct mlx5e_flow_table *ft,
 		break;
 	default:
 		err = -EINVAL;
-		goto out;
+		goto free_ft;
 	}
 
 	MLX5_SET_CFG(in, match_criteria_enable, MLX5_MATCH_OUTER_HEADERS);
@@ -327,7 +328,9 @@ static int arfs_create_groups(struct mlx5e_flow_table *ft,
 err:
 	err = PTR_ERR(ft->g[ft->num_groups]);
 	ft->g[ft->num_groups] = NULL;
-out:
+free_ft:
+	kfree(ft->g);
+	ft->g = NULL;
 	kvfree(in);
 
 	return err;
@@ -343,8 +346,6 @@ static int arfs_create_table(struct mlx5e_flow_steering *fs,
 	struct mlx5_flow_table_attr ft_attr = {};
 	int err;
 
-	ft->num_groups = 0;
-
 	ft_attr.max_fte = MLX5E_ARFS_TABLE_SIZE;
 	ft_attr.level = MLX5E_ARFS_FT_LEVEL;
 	ft_attr.prio = MLX5E_NIC_PRIO;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
index 777d311d44ef..7b6aa0c8b58d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
@@ -883,7 +883,6 @@ void mlx5e_fs_init_l2_addr(struct mlx5e_flow_steering *fs, struct net_device *ne
 void mlx5e_destroy_flow_table(struct mlx5e_flow_table *ft)
 {
 	mlx5e_destroy_groups(ft);
-	kfree(ft->g);
 	mlx5_destroy_flow_table(ft->t);
 	ft->t = NULL;
 }
-- 
2.34.1