2018-05-10 07:06:28

by Christophe JAILLET

Subject: [PATCH v2] net/mlx4_en: Fix an error handling path in 'mlx4_en_init_netdev()'

If an error occurs, 'mlx4_en_destroy_netdev()' is called.
It then calls 'mlx4_en_free_resources()' which does the needed resources
cleanup.

So, doing some explicit kfree in the error handling path would lead to
some double kfree.

Simplify code to avoid such a case.

Fixes: 67f8b1dcb9ee ("net/mlx4_en: Refactor the XDP forwarding rings scheme")
Signed-off-by: Christophe JAILLET <[email protected]>
---
v1 -> v2 : rewrite the fix as explained by Tariq Toukan
(this 2nd version may have been posted twice, once without the
v2 tag. PLease ignore the first one)
---

drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index e0adac4a9a19..9670b33fc9b1 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -3324,12 +3324,11 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
MAX_TX_RINGS, GFP_KERNEL);
if (!priv->tx_ring[t]) {
err = -ENOMEM;
- goto err_free_tx;
+ goto out;
}
priv->tx_cq[t] = kzalloc(sizeof(struct mlx4_en_cq *) *
MAX_TX_RINGS, GFP_KERNEL);
if (!priv->tx_cq[t]) {
- kfree(priv->tx_ring[t]);
err = -ENOMEM;
goto out;
}
@@ -3582,11 +3581,6 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,

return 0;

-err_free_tx:
- while (t--) {
- kfree(priv->tx_ring[t]);
- kfree(priv->tx_cq[t]);
- }
out:
mlx4_en_destroy_netdev(dev);
return err;
--
2.17.0

2018-05-10 12:43:08

by Tariq Toukan

Subject: Re: [PATCH v2] net/mlx4_en: Fix an error handling path in 'mlx4_en_init_netdev()'

On 10/05/2018 10:06 AM, Christophe JAILLET wrote:
> If an error occurs, 'mlx4_en_destroy_netdev()' is called.
> It then calls 'mlx4_en_free_resources()' which does the needed resources
> cleanup.
>
> So, doing some explicit kfree in the error handling path would lead to
> some double kfree.
>
> Simplify code to avoid such a case.
>
> Fixes: 67f8b1dcb9ee ("net/mlx4_en: Refactor the XDP forwarding rings scheme")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> v1 -> v2 : rewrite the fix as explained by Tariq Toukan
> (this 2nd version may have been posted twice, once without the
> v2 tag. PLease ignore the first one)
> ---
>
> drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> index e0adac4a9a19..9670b33fc9b1 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> @@ -3324,12 +3324,11 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
> MAX_TX_RINGS, GFP_KERNEL);
> if (!priv->tx_ring[t]) {
> err = -ENOMEM;
> - goto err_free_tx;
> + goto out;
> }
> priv->tx_cq[t] = kzalloc(sizeof(struct mlx4_en_cq *) *
> MAX_TX_RINGS, GFP_KERNEL);
> if (!priv->tx_cq[t]) {
> - kfree(priv->tx_ring[t]);
> err = -ENOMEM;
> goto out;
> }
> @@ -3582,11 +3581,6 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
>
> return 0;
>
> -err_free_tx:
> - while (t--) {
> - kfree(priv->tx_ring[t]);
> - kfree(priv->tx_cq[t]);
> - }
> out:
> mlx4_en_destroy_netdev(dev);
> return err;
>

Reviewed-by: Tariq Toukan <[email protected]>

Thanks Christophe.

2018-05-10 21:48:16

by David Miller

Subject: Re: [PATCH v2] net/mlx4_en: Fix an error handling path in 'mlx4_en_init_netdev()'

From: Christophe JAILLET <[email protected]>
Date: Thu, 10 May 2018 09:06:04 +0200

> If an error occurs, 'mlx4_en_destroy_netdev()' is called.
> It then calls 'mlx4_en_free_resources()' which does the needed resources
> cleanup.
>
> So, doing some explicit kfree in the error handling path would lead to
> some double kfree.
>
> Simplify code to avoid such a case.
>
> Fixes: 67f8b1dcb9ee ("net/mlx4_en: Refactor the XDP forwarding rings scheme")
> Signed-off-by: Christophe JAILLET <[email protected]>

Applied and queued up for -stable, thanks.