Re: [PATCH net v3 2/2] bonding: 802.3ad: fix no transmission of LACPDUs

[Hangbin Liu <liuhangbin@gmail.com>]

On Mon, Aug 15, 2022 at 11:08:35AM -0400, Jonathan Toppins wrote:
> This is caused by the global variable ad_ticks_per_sec being zero as
> demonstrated by the reproducer script discussed below. This causes
> all timer values in __ad_timer_to_ticks to be zero, resulting
> in the periodic timer to never fire.
> 
> To reproduce:
> Run the script in
> `tools/testing/selftests/drivers/net/bonding/bond-break-lacpdu-tx.sh` which
> puts bonding into a state where it never transmits LACPDUs.
> 
> line 44: ip link add fbond type bond mode 4 miimon 200 \
>             xmit_hash_policy 1 ad_actor_sys_prio 65535 lacp_rate fast
> setting bond param: ad_actor_sys_prio
> given:
>     params.ad_actor_system = 0
> call stack:
>     bond_option_ad_actor_sys_prio()
>     -> bond_3ad_update_ad_actor_settings()
>        -> set ad.system.sys_priority = bond->params.ad_actor_sys_prio
>        -> ad.system.sys_mac_addr = bond->dev->dev_addr; because
>             params.ad_actor_system == 0
> results:
>      ad.system.sys_mac_addr = bond->dev->dev_addr
> 
> line 48: ip link set fbond address 52:54:00:3B:7C:A6
> setting bond MAC addr
> call stack:
>     bond->dev->dev_addr = new_mac
> 
> line 52: ip link set fbond type bond ad_actor_sys_prio 65535
> setting bond param: ad_actor_sys_prio
> given:
>     params.ad_actor_system = 0
> call stack:
>     bond_option_ad_actor_sys_prio()
>     -> bond_3ad_update_ad_actor_settings()
>        -> set ad.system.sys_priority = bond->params.ad_actor_sys_prio
>        -> ad.system.sys_mac_addr = bond->dev->dev_addr; because
>             params.ad_actor_system == 0
> results:
>      ad.system.sys_mac_addr = bond->dev->dev_addr
> 
> line 60: ip link set veth1-bond down master fbond
> given:
>     params.ad_actor_system = 0
>     params.mode = BOND_MODE_8023AD
>     ad.system.sys_mac_addr == bond->dev->dev_addr
> call stack:
>     bond_enslave
>     -> bond_3ad_initialize(); because first slave
>        -> if ad.system.sys_mac_addr != bond->dev->dev_addr
>           return
> results:
>      Nothing is run in bond_3ad_initialize() because dev_add equals
>      sys_mac_addr leaving the global ad_ticks_per_sec zero as it is
>      never initialized anywhere else.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Jonathan Toppins <jtoppins@redhat.com>
> ---
> 
> Notes:
>     v2:
>      * split this fix from the reproducer
>     v3:
>      * rebased to latest net/master
> 
>  drivers/net/bonding/bond_3ad.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
> index d7fb33c078e8..957d30db6f95 100644
> --- a/drivers/net/bonding/bond_3ad.c
> +++ b/drivers/net/bonding/bond_3ad.c
> @@ -84,7 +84,8 @@ enum ad_link_speed_type {
>  static const u8 null_mac_addr[ETH_ALEN + 2] __long_aligned = {
>  	0, 0, 0, 0, 0, 0
>  };
> -static u16 ad_ticks_per_sec;
> +
> +static u16 ad_ticks_per_sec = 1000 / AD_TIMER_INTERVAL;
>  static const int ad_delta_in_ticks = (AD_TIMER_INTERVAL * HZ) / 1000;
>  
>  static const u8 lacpdu_mcast_addr[ETH_ALEN + 2] __long_aligned =
> -- 
> 2.31.1
> 

Acked-by: Hangbin Liu <liuhangbin@gmail.com>