Re: [PATCH RFC batadv] batman-adv: mcast: fix use-after-free in orig_node RCU release

On Sun, May 17, 2026 at 06:54:09PM +0200, Sven Eckelmann wrote:
> But this looks super RCU-like (without locks):
> 
> static int
> batadv_mcast_forw_want_all_ipv4(struct batadv_priv *bat_priv,
> 				struct sk_buff *skb, unsigned short vid)
> {
> 	struct batadv_orig_node *orig_node;
> 	int ret = NET_XMIT_SUCCESS;
> 	struct sk_buff *newskb;
> 
> 	rcu_read_lock();
> 	hlist_for_each_entry_rcu(orig_node,
> 				 &bat_priv->mcast.want_all_ipv4_list,
> 				 mcast_want_all_ipv4_node) {
> [..]
> 	}
> 	rcu_read_unlock();
> 	return ret;
> }

Ah, no, you're absolutely right, I mixed it up!

Maybe this might make more sense as a fixes line then, though?

Fixes: 500ea14940f8 ("batman-adv: Add multicast-to-unicast support for multiple targets")


I think before that commit we only used these atomic counters in
fast path?