[PATCH 3/3] net/mlx5e: Fix use of freed pointer

From: Alex Dewar
Date: Sun Sep 27 2020 - 07:33:33 EST


If the call to mlx5_fc_create() fails, then shared_counter will be freed
before its member, shared_counter->counter, is accessed to retrieve the
error code. Fix by using an intermediate variable.

Addresses-Coverity: CID 1497153: Memory - illegal accesses (USE_AFTER_FREE)
Signed-off-by: Alex Dewar <alex.dewar90@xxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
index b5f8ed30047b..5851a1dfe6e4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
@@ -738,6 +738,7 @@ mlx5_tc_ct_shared_counter_get(struct mlx5_tc_ct_priv *ct_priv,
struct mlx5_ct_shared_counter *shared_counter;
struct mlx5_core_dev *dev = ct_priv->dev;
struct mlx5_ct_entry *rev_entry;
+ struct mlx5_fc *counter;
__be16 tmp_port;

/* get the reversed tuple */
@@ -775,12 +776,13 @@ mlx5_tc_ct_shared_counter_get(struct mlx5_tc_ct_priv *ct_priv,
if (!shared_counter)
return ERR_PTR(-ENOMEM);

- shared_counter->counter = mlx5_fc_create(dev, true);
- if (IS_ERR(shared_counter->counter)) {
+ counter = mlx5_fc_create(dev, true);
+ if (IS_ERR(counter)) {
ct_dbg("Failed to create counter for ct entry");
kfree(shared_counter);
- return ERR_PTR(PTR_ERR(shared_counter->counter));
+ return (struct mlx5_ct_shared_counter *)counter;
}
+ shared_counter->counter = counter;

refcount_set(&shared_counter->refcount, 1);
return shared_counter;
--
2.28.0