Re: [PATCH nf] netfilter: ipset: let destroy callbacks adjust ext mem size

Hi Florian,

On Tue, 4 Aug 2026, Florian Westphal wrote:

> For bitmap this change makes no difference, because destructors are
> called synchronously.
> 
> sashiko pointed out list type destruction is partially done via call_rcu:
> mem accounting could be subtracting after list_set_flush() did reset the
> value to 0.  set->elements assignment can be removed for the same reason,
> this already walks the entire set and does 'set->elements--' for each
> entry synchronously.

Yes, I agree, about set->elements too. And one DEBUG_NET_WARN_ON_ONCE() is 
enough and it should catch any problem in list_set_del() about element 
number or extension size.
 
> Fixes: 9e41f26a505c ("netfilter: ipset: Count non-static extension memory for userspace")
> Signed-off-by: Florian Westphal <[email protected]>
> ---
>  Won't apply, this assumes the pending nf PR is applied.
>  In case that PR is rejected, this patch could be
>  reworked to logically come before the atomic64 conversion,
>  but it doesn't buy mutch.
> 
>  net/netfilter/ipset/ip_set_bitmap_gen.h | 2 +-
>  net/netfilter/ipset/ip_set_list_set.c   | 3 +--
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h b/net/netfilter/ipset/ip_set_bitmap_gen.h
> index 226fdf17b683..d6a7e6604542 100644
> --- a/net/netfilter/ipset/ip_set_bitmap_gen.h
> +++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
> @@ -77,7 +77,7 @@ mtype_flush(struct ip_set *set)
>  		mtype_ext_cleanup(set);
>  	bitmap_zero(map->members, map->elements);
>  	set->elements = 0;
> -	atomic64_set(&set->ext_size, 0);
> +	DEBUG_NET_WARN_ON_ONCE(atomic64_read(&set->ext_size) > 0);
>  }
>  
>  /* Calculate the actual memory size of the set data */
> diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
> index ca3ef9479e83..024de3bc9fc3 100644
> --- a/net/netfilter/ipset/ip_set_list_set.c
> +++ b/net/netfilter/ipset/ip_set_list_set.c
> @@ -420,8 +420,7 @@ list_set_flush(struct ip_set *set)
>  
>  	list_for_each_entry_safe(e, n, &map->members, list)
>  		list_set_del(set, e);
> -	set->elements = 0;
> -	atomic64_set(&set->ext_size, 0);
> +	DEBUG_NET_WARN_ON_ONCE(set->elements > 0);
>  }
>  
>  static void
> -- 

Acked-by: Jozsef Kadlecsik <[email protected]>

Best regards,
Jozsef
-- 
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