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From:   Moshe Shemesh <moshes20.il@gmail.com>
Date:   Mon, 19 Aug 2019 16:00:53 +0300
Message-ID: <CALBF4T_xmmAyTpPRfuC0a_C+TpX5xbA9+U1JxUJ6p1RvUFjGHQ@mail.gmail.com>
Subject: Re: [PATCH] net/mlx5: Fix a memory leak bug
To:     Wenwen Wang <wenwen@cs.uga.edu>
Cc:     Saeed Mahameed <saeedm@mellanox.com>,
        Leon Romanovsky <leon@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        "open list:MELLANOX MLX5 core VPI driver" <netdev@vger.kernel.org>,
        "open list:MELLANOX MLX5 core VPI driver" 
        <linux-rdma@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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Please don't change that.
On command timeout we don't release ent, since the FW event on
completion can occur after timeout, so it is released on the
completion handler mlx5_cmd_comp_handler().
See commit 73dd3a4839c1d ("net/mlx5: Avoid using pending command
interface slots").

On Tue, Aug 13, 2019 at 11:22 AM Wenwen Wang <wenwen@cs.uga.edu> wrote:
>
> In mlx5_cmd_invoke(), 'ent' is allocated through kzalloc() in alloc_cmd().
> After the work is queued, wait_func() is invoked to wait the completion of
> the work. If wait_func() returns -ETIMEDOUT, the following execution will
> be terminated. However, the allocated 'ent' is not deallocated on this
> program path, leading to a memory leak bug.
>
> To fix the above issue, free 'ent' before returning the error.
>
> Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> index 8cdd7e6..90cdb9a 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> @@ -1036,7 +1036,7 @@ static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in,
>
>         err = wait_func(dev, ent);
>         if (err == -ETIMEDOUT)
> -               goto out;
> +               goto out_free;
>
>         ds = ent->ts2 - ent->ts1;
>         op = MLX5_GET(mbox_in, in->first.data, opcode);
> --
> 2.7.4
>