Re: [PATCH net 4/4] bonding: fix xfrm state handling when clearing active slave

[Hangbin Liu <liuhangbin@gmail.com>]

On Fri, Aug 16, 2024 at 02:48:13PM +0300, Nikolay Aleksandrov wrote:
> If the active slave is cleared manually the xfrm state is not flushed.
> This leads to xfrm add/del imbalance and adding the same state multiple
> times. For example when the device cannot handle anymore states we get:
>  [ 1169.884811] bond0: (slave eni0np1): bond_ipsec_add_sa_all: failed to add SA
> because it's filled with the same state after multiple active slave
> clearings. This change also has a few nice side effects: user-space
> gets a notification for the change, the old device gets its mac address
> and promisc/mcast adjusted properly.
> 
> Fixes: 18cb261afd7b ("bonding: support hardware encryption offload to slaves")
> Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
> ---
> Please review this one more carefully. I plan to add a selftest with
> netdevsim for this as well.
> 
>  drivers/net/bonding/bond_options.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
> index bc80fb6397dc..95d59a18c022 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
> @@ -936,7 +936,7 @@ static int bond_option_active_slave_set(struct bonding *bond,
>  	/* check to see if we are clearing active */
>  	if (!slave_dev) {
>  		netdev_dbg(bond->dev, "Clearing current active slave\n");
> -		RCU_INIT_POINTER(bond->curr_active_slave, NULL);
> +		bond_change_active_slave(bond, NULL);

The good part of this is we can do bond_ipsec_del_sa_all and
bond_ipsec_add_sa_all. I'm not sure if we should do promisc/mcast adjustment
when set active_slave to null.

Jay should know better.

Thanks
Hangbin
>  		bond_select_active_slave(bond);
>  	} else {
>  		struct slave *old_active = rtnl_dereference(bond->curr_active_slave);
> -- 
> 2.44.0
>