Re: [PATCH net-next] mlx5: Restore err assignment in mlx5_mdev_init

From: Leon Romanovsky
Date: Sun May 31 2020 - 05:58:16 EST


On Fri, May 29, 2020 at 10:54:48PM -0700, Nathan Chancellor wrote:
> Clang warns:
>
> drivers/net/ethernet/mellanox/mlx5/core/main.c:1278:6: warning: variable
> 'err' is used uninitialized whenever 'if' condition is true
> [-Wsometimes-uninitialized]
> if (!priv->dbg_root) {
> ^~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/main.c:1303:9: note:
> uninitialized use occurs here
> return err;
> ^~~
> drivers/net/ethernet/mellanox/mlx5/core/main.c:1278:2: note: remove the
> 'if' if its condition is always false
> if (!priv->dbg_root) {
> ^~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/main.c:1259:9: note: initialize
> the variable 'err' to silence this warning
> int err;
> ^
> = 0
> 1 warning generated.
>
> This path previously returned -ENOMEM, restore that error code so that
> it is not uninitialized.
>
> Fixes: 810cbb25549b ("net/mlx5: Add missing mutex destroy")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1042
> Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/main.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> index df46b1fce3a7..ac68445fde2d 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> @@ -1277,6 +1277,7 @@ static int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx)
> mlx5_debugfs_root);
> if (!priv->dbg_root) {
> dev_err(dev->device, "mlx5_core: error, Cannot create debugfs dir, aborting\n");
> + err = -ENOMEM;
> goto err_dbg_root;
^^^^^^^^^^^^^^^^^^ this is wrong.
Failure to create debugfs should never fail the driver.

> }
>
>
> base-commit: c0cc73b79123e67b212bd537a7af88e52c9fbeac
> --
> 2.27.0.rc0
>