On 6/4/2024 3:05 AM, Aleksandr Mishin wrote:
> In case of flow rule creation fail in mlx5_lag_create_port_sel_table(),
> instead of previously created rules, the tainted pointer is deleted
> deveral times.
> Fix this bug by using correct flow rules pointers.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 352899f384d4 ("net/mlx5: Lag, use buckets in hash mode")
> Signed-off-by: Aleksandr Mishin <amishin@xxxxxxxxxx>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/lag/port_sel.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/port_sel.c b/drivers/net/ethernet/mellanox/mlx5/core/lag/port_sel.c
> index c16b462ddedf..ab2717012b79 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/lag/port_sel.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/port_sel.c
> @@ -88,9 +88,13 @@ static int mlx5_lag_create_port_sel_table(struct mlx5_lag *ldev,
> &dest, 1);
> if (IS_ERR(lag_definer->rules[idx])) {
> err = PTR_ERR(lag_definer->rules[idx]);
> - while (i--)
> - while (j--)
> + do {
> + while (j--) {
> + idx = i * ldev->buckets + j;
> mlx5_del_flow_rules(lag_definer->rules[idx]);
> + }
> + j = ldev->buckets;
> + } while (i--);
So, before the code was:
while (i--)
while (j--)
mlx5_del_flow_rules(lag_definer->rules[idx]);
That just calls mlx5_del_flow_rules a bunch of times but keeps using the
wrong index, which is obviously wrong.
The new fix is to calculate the index properly (hence the switch to a do
{ } while (0) loop, so that we properly delete all of the older rules
rather than calling mlx5_del_flow_rules multiple times on the wrong index.
Makes sense.
Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
> goto destroy_fg;
> }
> }
