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From:   Colin Ian King <colin.i.king@gmail.com>
To:     Saeed Mahameed <saeedm@nvidia.com>,
        Leon Romanovsky <leon@kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Roi Dayan <roid@nvidia.com>, netdev@vger.kernel.org,
        linux-rdma@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
Subject: [PATCH] net/mlx5e: Fix return of a kfree'd object instead of NULL
Date:   Thu, 24 Feb 2022 22:15:24 +0000
Message-Id: <20220224221525.147744-1-colin.i.king@gmail.com>
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Precedence: bulk

Currently in the case where parse_attr fails to be allocated the memory
pointed to by attr2 is kfree'd but the non-null pointer attr2 is returned
and a potential use of a kfree'd object can occur.  Fix this by returning
NULL to indicate a memory allocation error.

Addresses issue found by clang-scan:
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:3401:3: warning: Use of
memory after it is freed [unix.Malloc]

Fixes: 8300f225268b ("net/mlx5e: Create new flow attr for multi table actions")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 76a015dfc5fc..c0776a4a3845 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -3398,7 +3398,7 @@ mlx5e_clone_flow_attr_for_post_act(struct mlx5_flow_attr *attr,
 	if (!attr2 || !parse_attr) {
 		kvfree(parse_attr);
 		kfree(attr2);
-		return attr2;
+		return NULL;
 	}
 
 	memcpy(attr2, attr, attr_sz);
-- 
2.34.1