Re: [B.A.T.M.A.N.] [PATCH 1/3] batman-adv: fix lockdep splat when doing mcast_free

[Antonio Quartulli <antonio@meshcoding.com>]

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Simon Wunderlich:
> From: Simon Wunderlich <simon@open-mesh.com>
> 
> Signed-off-by: Simon Wunderlich <simon@open-mesh.com>
> ---
>  net/batman-adv/multicast.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
> index 8abf488..d984eee 100644
> --- a/net/batman-adv/multicast.c
> +++ b/net/batman-adv/multicast.c
> @@ -801,7 +801,9 @@ void batadv_mcast_free(struct batadv_priv *bat_priv)
>  	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_MCAST, 1);
>  	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_MCAST, 1);
>  
> +	spin_lock_bh(&bat_priv->tt.commit_lock);
>  	batadv_mcast_mla_tt_retract(bat_priv, NULL);
> +	spin_unlock_bh(&bat_priv->tt.commit_lock);

Linus,

can you please comment as of why batadv_mcast_mla_tt_retract() requires
to hold the tt.commit_lock ?


I see it calls batadv_tt_local_remove() but this does not really
requires the lock. Maybe you wanted to perform *all* the removes before
TT could do a commit ? Or is there any other reason?

Cheers,

-- 
Antonio Quartulli


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