From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 876D525A2A4; Fri, 6 Feb 2026 15:31:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770391889; cv=none; b=cYMsO8ZNTLrRifnKZdGh8T1NVvDPpEXY8qBhhRrrxsmxpvi5LYQGDPzMESa13k2aJNBpVepzu42pFyogGSy1cg8D9f9R5w7kU5UkIm4y482dpYF8yQ1vvAMrzMMAg3ncyRIHxVeXa4w23YizuAhHZJunDVJalLM5sGBjKtoVBms= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770391889; c=relaxed/simple; bh=eOwPMXuSN3Uvd0pghwDe/+QshT9FsZzUGwrs9iN0ikU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z8E9gi8MjfmEoZQzqR0B9fSqYdX37LO16z1QOeCVUVayLAZUYOhcGxY6qq9IC0BQvu3kuALtHNmVI40ciaI/D3yV0/k0AaM3mVHgnF7S80st8p/7q7qsR5AdSmGDHMAhDH8i98Bjnxb+zKiYhBBTbM4PaCeAtK8MEBEougHoLkA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 234F3607E0; Fri, 06 Feb 2026 16:31:28 +0100 (CET) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH v2 net-next 07/11] netfilter: nft_counter: fix reset of counters on 32bit archs Date: Fri, 6 Feb 2026 16:30:44 +0100 Message-ID: <20260206153048.17570-8-fw@strlen.de> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260206153048.17570-1-fw@strlen.de> References: <20260206153048.17570-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Anders Grahn 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.") Signed-off-by: Anders Grahn Signed-off-by: Florian Westphal --- include/linux/u64_stats_sync.h | 10 ++++++++++ net/netfilter/nft_counter.c | 4 ++-- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h index 849ff6e159c6..f47cf4d78ad7 100644 --- a/include/linux/u64_stats_sync.h +++ b/include/linux/u64_stats_sync.h @@ -97,6 +97,11 @@ static inline void u64_stats_add(u64_stats_t *p, unsigned long val) local64_add(val, &p->v); } +static inline void u64_stats_sub(u64_stats_t *p, s64 val) +{ + local64_sub(val, &p->v); +} + static inline void u64_stats_inc(u64_stats_t *p) { local64_inc(&p->v); @@ -145,6 +150,11 @@ static inline void u64_stats_add(u64_stats_t *p, unsigned long val) p->v += val; } +static inline void u64_stats_sub(u64_stats_t *p, s64 val) +{ + p->v -= val; +} + static inline void u64_stats_inc(u64_stats_t *p) { p->v++; diff --git a/net/netfilter/nft_counter.c b/net/netfilter/nft_counter.c index cc7325329496..0d70325280cc 100644 --- a/net/netfilter/nft_counter.c +++ b/net/netfilter/nft_counter.c @@ -117,8 +117,8 @@ static void nft_counter_reset(struct nft_counter_percpu_priv *priv, nft_sync = this_cpu_ptr(&nft_counter_sync); u64_stats_update_begin(nft_sync); - u64_stats_add(&this_cpu->packets, -total->packets); - u64_stats_add(&this_cpu->bytes, -total->bytes); + u64_stats_sub(&this_cpu->packets, total->packets); + u64_stats_sub(&this_cpu->bytes, total->bytes); u64_stats_update_end(nft_sync); local_bh_enable(); -- 2.52.0