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Message-ID: <3d3b6a1f-40b6-45b5-a899-d01acb91213d@gmail.com>
Date:   Tue, 28 Nov 2023 10:58:04 +0200
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] net/mlx5e: fix a potential double-free in
 fs_any_create_groups
Content-Language: en-US
To:     Dinghao Liu <dinghao.liu@zju.edu.cn>
Cc:     Saeed Mahameed <saeedm@nvidia.com>,
        Leon Romanovsky <leon@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Zhengchao Shao <shaozhengchao@huawei.com>,
        Rahul Rameshbabu <rrameshbabu@nvidia.com>,
        Simon Horman <horms@kernel.org>,
        Tariq Toukan <tariqt@nvidia.com>, Aya Levin <ayal@nvidia.com>,
        netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org, Tariq Toukan <tariqt@nvidia.com>
References: <20231128082812.24483-1-dinghao.liu@zju.edu.cn>
From:   Tariq Toukan <ttoukan.linux@gmail.com>
In-Reply-To: <20231128082812.24483-1-dinghao.liu@zju.edu.cn>
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On 28/11/2023 10:28, Dinghao Liu wrote:
> When kcalloc() for ft->g succeeds but kvzalloc() for in fails,
> fs_any_create_groups() will free ft->g. However, its caller
> fs_any_create_table() will free ft->g again through calling
> mlx5e_destroy_flow_table(), which will lead to a double-free.
> Fix this by removing the kfree(ft->g) in fs_any_create_groups().
> 
> Fixes: 0f575c20bf06 ("net/mlx5e: Introduce Flow Steering ANY API")
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/en/fs_tt_redirect.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/fs_tt_redirect.c b/drivers/net/ethernet/mellanox/mlx5/core/en/fs_tt_redirect.c
> index be83ad9db82a..b222d23bfb9a 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/fs_tt_redirect.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/fs_tt_redirect.c
> @@ -434,7 +434,6 @@ static int fs_any_create_groups(struct mlx5e_flow_table *ft)
>   	ft->g = kcalloc(MLX5E_FS_UDP_NUM_GROUPS, sizeof(*ft->g), GFP_KERNEL);
>   	in = kvzalloc(inlen, GFP_KERNEL);
>   	if  (!in || !ft->g) {
> -		kfree(ft->g);
>   		kvfree(in);
>   		return -ENOMEM;
>   	}

Function fs_any_create_groups should not return failure without cleaning 
itself up. This is not the right fix.
Freeing ft->g and setting it to NULL will do it, and will avoid the 
double free.