Re: [bug report] net/mlx5e: Handle FIB events to update tunnel endpoint device

[Vlad Buslov <vladbu@nvidia.com>]

On Wed 10 Feb 2021 at 13:08, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> Hello Vlad Buslov,
>
> The patch 8914add2c9e5: "net/mlx5e: Handle FIB events to update
> tunnel endpoint device" from Jan 25, 2021, leads to the following
> static checker warning:
>
> 	drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c:1639 mlx5e_tc_tun_init()
> 	error: passing non negative 1 to ERR_PTR
>
> drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c
>   1622  struct mlx5e_tc_tun_encap *mlx5e_tc_tun_init(struct mlx5e_priv *priv)
>   1623  {
>   1624          struct mlx5e_tc_tun_encap *encap;
>   1625          int err;
>   1626  
>   1627          encap = kvzalloc(sizeof(*encap), GFP_KERNEL);
>   1628          if (!encap)
>   1629                  return ERR_PTR(-ENOMEM);
>   1630  
>   1631          encap->priv = priv;
>   1632          encap->fib_nb.notifier_call = mlx5e_tc_tun_fib_event;
>   1633          spin_lock_init(&encap->route_lock);
>   1634          hash_init(encap->route_tbl);
>   1635          err = register_fib_notifier(dev_net(priv->netdev), &encap->fib_nb,
>   1636                                      NULL, NULL);
>
> register_fib_notifier() calls fib_net_dump() which eventually calls
> fib6_walk_continue() which can return 1 if "walk is incomplete (i.e.
> suspended)".
>
>   1637          if (err) {
>   1638                  kvfree(encap);
>   1639                  return ERR_PTR(err);
>
> If this returns 1 it will eventually lead to an Oops.

Hi Dan,

Thanks for the bug report!

This looks a bit strange to me because none of the other users of this
API handle positive error code in any special way (including reference
netdevsim implementation). Maybe API itself should be fixed? Jiri, Ido,
what do you think?

Regards,
Vlad

>
>   1640          }
>   1641  
>   1642          return encap;
>   1643  }
>
> regards,
> dan carpenter