From: Simon Horman <horms@kernel.org>
To: Anders Grahn <anders.grahn@gmail.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@netfilter.org>,
Florian Westphal <fw@strlen.de>, Phil Sutter <phil@nwl.cc>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Anders Grahn <anders.grahn@westermo.com>,
linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org,
coreteam@netfilter.org, netdev@vger.kernel.org
Subject: Re: [PATCH] netfilter: nft_counter: Fix reset of counters on 32bit archs
Date: Mon, 15 Dec 2025 14:54:05 +0000 [thread overview]
Message-ID: <aUAhDdMGykBb2BOg@horms.kernel.org> (raw)
In-Reply-To: <20251215121258.843823-1-anders.grahn@westermo.com>
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@westermo.com>
...
prev parent reply other threads:[~2025-12-15 14:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-15 12:12 [PATCH] netfilter: nft_counter: Fix reset of counters on 32bit archs Anders Grahn
2025-12-15 12:36 ` Florian Westphal
2025-12-15 13:53 ` David Laight
2025-12-15 14:01 ` Anders Grahn
2025-12-15 14:54 ` Simon Horman [this message]
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