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Date:   Tue, 19 Mar 2019 08:14:31 +0200
From:   Leon Romanovsky <leon@kernel.org>
To:     Aditya Pakki <pakki001@umn.edu>,
        Boris Pismeny <borisp@mellanox.com>,
        Saeed Mahameed <saeedm@mellanox.com>
Cc:     kjlu@umn.edu, "David S. Miller" <davem@davemloft.net>,
        Wei Yongjun <weiyongjun1@huawei.com>, netdev@vger.kernel.org,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: mlx5: Add a missing check on idr_find
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On Mon, Mar 18, 2019 at 05:18:51PM -0500, Aditya Pakki wrote:
> idr_find() can return a NULL value to 'flow' which is used without a check.
> The patch adds a check to avoid potential NULL pointer dereference.
>
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> index 5cf5f2a9d51f..3df468acdffc 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> @@ -226,6 +226,8 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
>  	rcu_read_lock();
>  	flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
>  	rcu_read_unlock();
> +	if (!flow)
> +		return -EINVAL;

It is wrong and whole function is wrong too.
In such case, you will leak "buf" allocated above.

The function mlx5_fpga_sbu_conn_sendmsg() which is used below can fail
and it will leave "buf" unfreed too.

Thanks


>  	mlx5_fpga_tls_flow_to_cmd(flow, cmd);
>
>  	MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
> --
> 2.17.1
>

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