Re: [PATCH] netfilter: nft_counter: Fix reset of counters on 32bit archs

[Simon Horman]

On Mon, Dec 15, 2025 at 01:12:57PM +0100, Anders Grahn wrote:
> nft_counter_reset() calls u64_stats_add() with a negative value to reset
> the counter. This will work on 64bit archs, hence the negative value
> added will wrap as a 64bit value which then can wrap the stat counter as
> well.
> 
> On 32bit archs, the added negative value will wrap as a 32bit value and
> _not_ wrapping the stat counter properly. In most cases, this would just
> lead to a very large 32bit value being added to the stat counter.
> 
> Fix by introducing u64_stats_sub().
> 
> Fixes: 4a1d3acd6ea8 ("netfilter: nft_counter: Use u64_stats_t for statistic")

Nit: there is a minor mismatch in the subject of the Fixes tag and
     git history: the trailing '.'
     I would go for this. But perhaps it doesn't matter.

Fixes: 4a1d3acd6ea8 ("netfilter: nft_counter: Use u64_stats_t for statistic.")

> Signed-off-by: Anders Grahn <anders.grahn@xxxxxxxxxxxx>

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