From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792783863; b=t7VBs056jvSVqNnN2MORDhrqtninFiPA2w43imiZBOi4yhkbJV4gyGLgCnnd0l2umQ7f nmrQXYlc64xCV8goV+7haQIP+tNy/yRG1FoNF+/LYnOuo/7RnzbbeASmeiXKJAICDAgJA BoEMy/KgR+cheO33c7kkM6IQVlRDb2RoqszRSTQcsWWQrkFjP5VjabeXb+GlD7W/ARfS/ dwlr30bajs/qEOSiUcjlGvyYoBRI71/xmnY33DXoPVt8Mk9fropexLxM4HK7+7PZ6Sb32 /sToyJICcEW9wLfEPjTSAQUhZRtKCeOEIRrH21nvkgWxaM4RC/3mwR2/WhAmgOXUifQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792783863; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=nB2gaoU0hmYvZYSoXJf1tRJ5p2ObyHTPEEeKB+5Oz3s=; b=gDOQRduHp+kTAXnKcX01W0F4PbFtY67gGhaZiKRaljQtN/J1UN9buAleQonzZw7ySX/d YLS1dKN0DEFwzm8dZinqyaS4jdZ4sN18fY8yc9L7idMK40GsBLyrUPnVgtKEdnrLVGEe8 HYxyxpBACPSKanESLuYqAzptsIJpfO3aR2Gw2YuObzF2im+ESWk00zumMzJ7ALQx/gKjE wEn/kxNGW0pX21thervpZwKJsuywt3njPw+ffDPole8TW9PyWQ80Av5d26WQ9kosyriTP VzDj+BSzzbLC3Sk5ndi7aEAuZeWuRd2p3vzSCv3HtO+CPkOeZXzbMsC/BjS1y5w1WZA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="oogApd/W"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 813CE606A320; Fri, 23 Oct 2026 19:31:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oogApd/W Received: by smtp.kernel.org (Postfix) with ESMTPSA id C43861F01825; Fri, 23 Oct 2026 19:31:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792783863; bh=nB2gaoU0hmYvZYSoXJf1tRJ5p2ObyHTPEEeKB+5Oz3s=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=oogApd/WS+Wgs4M/5dynlevYmslCFO08SV4zPf/i1+eI0MDn+qgQwsOmC9wIfg73G YTxEcLF0c4vN/qiXOXLB2WLPIAzUXVg6R/+o2xA6wuN3fbhuZlhO3jU7fXEtxaRzvh 5F34fSK1h0ns/alwgUfCndYKd7fFQMNSJBV9c1e1Iif4y0BRmx5zrWlhzBN9TiN4nx HlbLXrn0JRsBcbFqs5yLcpTNLgML0cjMfzTyJ+q9UUW0jgGqNPlq0NEamEIvmGlAS/ 9hhoGhn1q1eU3Ptz7ka7RdQPboH0btxv/BJ9awuA5Fy0L7cGSXTfZn0Bp3jPgFBL6T 77JVjUcvQEcqA== Date: Fri, 23 Oct 2026 12:31:02 -0700 From: Jakub Kicinski To: Jiayuan Chen Cc: netdev@vger.kernel.org, stable@vger.kernel.org, "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Neal Cardwell , Joel Granados , Matthias Tafelmeier , linux-kernel@vger.kernel.org Subject: Re: [PATCH net] net: reject dev_weight products that overflow int Message-ID: <20261023123102.3c30d01e@kernel.org> In-Reply-To: <20261023114228.289161-1-jiayuan.chen@linux.dev> References: <20261023114228.289161-1-jiayuan.chen@linux.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 23 Oct 2026 19:42:25 +0800 Jiayuan Chen wrote: > proc_do_dev_weight() sets the backlog NAPI weight and the qdisc quota > to dev_weight * dev_weight_rx_bias and dev_weight * dev_weight_tx_bias. > The three sysctls only have a lower bound of 1, so the products can > overflow int and end up <= 0, e.g. dev_weight=65536 and > dev_weight_rx_bias=65536 give a backlog weight of 0. Not sure anyone uses these, maybe we could cap them? 1k for dev weight 8 for bias?