From nobody Tue Dec 2 00:46:42 2025 Received: from sender3-pp-f112.zoho.com (sender3-pp-f112.zoho.com [136.143.184.112]) (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 837E82FB99B; Mon, 24 Nov 2025 11:08:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.184.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763982495; cv=pass; b=f+/TqCGLLQAYypCKHpZRzjHNlkbAiTL6U1b3HmtUCHHdY7YOzZDPDwVoaQoBPK0ciAK/0q5CkY3tintastEXB/nO9HTDml2XyFsMjgPquseGmQeE4RYYRIOpLpnt6rm3szEeaHCX/M4LYzNdWc/5PKShm7yUbyqriBFOOi3yzyM= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763982495; c=relaxed/simple; bh=V5x8hVM3+HVrOj1QgAtegq88Chg4b2A5o5KIyuCPGg0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lt2GAxkYl+THHmS3X6d0TDaoJvDdCeC0tXTSn3QOaYh9TeKUU0sWQzllMW770Va/equW57SIGLuu8BRsRU3jXKrDE92c+Bi2hUIKa0FqCrL0heGsQZ/7VJISURUzk/vjkDMS+slynbUIBDlpyCHCnHwulV1sbzi5WaU995k0N2I= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=AVmokdW+; arc=pass smtp.client-ip=136.143.184.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="AVmokdW+" ARC-Seal: i=1; a=rsa-sha256; t=1763982473; cv=none; d=zohomail.com; s=zohoarc; b=nzoEES+ACjGpL2CgVFGgU3syBjERBvBzhN2kRTtThhbgqW8+KEXCK0p2EHEHLM5fmYE+JJjSPA5rMq32ZjhglrlDVH9XsrB7yTlhLGUfDHjcClXdhra+EBORdl8w0PuSl/020ArSCO6FfyP5LXSBfp4RiUvmGxyMyk8c7y5PQfM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1763982473; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=7+Y/LyMk0RrNOFdGUfyDXTf7l2qJ7k0vXn6vVykaLc8=; b=H4d4NAzp6dvdj1wstSaU088jgygaBkwHcYMTZKSYAtU0LBOWBbgWhkJReakAudE1jNU5tuiH4vIFatz4KtjjpogkVOn3BtxShyAPsWd8D8SRDyk+H4LsMsBiM85QL8wNwqJ8bkgyo8V/lJN/bdd5Eh5c6HveI4ys0+1gaBvbWmQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1763982473; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=7+Y/LyMk0RrNOFdGUfyDXTf7l2qJ7k0vXn6vVykaLc8=; b=AVmokdW+EbfVSbxse8mX8JqLaz73oLON4Ix1989B+b1JvAWx4APu8+U9BsER4k0j JRIJ1EUukJeQbhAIW7vtY41USUwALnigG3YDg3pP6vbhyXKgm9y+x+nOodTuzhqnwTS bfeZVLFjt02/L+A6PvQq2xPcbH6lrTv8C9GGOmFU= Received: by mx.zohomail.com with SMTPS id 1763982460325118.87585361846197; Mon, 24 Nov 2025 03:07:40 -0800 (PST) From: Nicolas Frattaroli Date: Mon, 24 Nov 2025 12:07:02 +0100 Subject: [PATCH v2 13/13] interconnect: mediatek: Aggregate bandwidth with saturating add Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251124-mt8196-dvfsrc-v2-13-d9c1334db9f3@collabora.com> References: <20251124-mt8196-dvfsrc-v2-0-d9c1334db9f3@collabora.com> In-Reply-To: <20251124-mt8196-dvfsrc-v2-0-d9c1334db9f3@collabora.com> To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Matthias Brugger , AngeloGioacchino Del Regno , Henry Chen , Georgi Djakov Cc: kernel@collabora.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-pm@vger.kernel.org, Nicolas Frattaroli X-Mailer: b4 0.14.3 By using a regular non-overflow-checking add, the MediaTek icc-emi driver will happy wrap at U32_MAX + 1 to 0. As it's common for the interconnect core to fill in INT_MAX values, this is not a hypothetical situation, but something that actually happens in regular use. This would be pretty disasterous if anything used this driver. Replace the addition with an overflow-checked addition from overflow.h, and saturate to U32_MAX if an overflow is detected. Fixes: b45293799f75 ("interconnect: mediatek: Add MediaTek MT8183/8195 EMI = Interconnect driver") Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Nicolas Frattaroli --- drivers/interconnect/mediatek/icc-emi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/interconnect/mediatek/icc-emi.c b/drivers/interconnect= /mediatek/icc-emi.c index 182aa2b0623a..dfa3a9cd9399 100644 --- a/drivers/interconnect/mediatek/icc-emi.c +++ b/drivers/interconnect/mediatek/icc-emi.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include =20 @@ -22,7 +23,9 @@ static int mtk_emi_icc_aggregate(struct icc_node *node, u= 32 tag, u32 avg_bw, { struct mtk_icc_node *in =3D node->data; =20 - *agg_avg +=3D avg_bw; + if (check_add_overflow(*agg_avg, avg_bw, agg_avg)) + *agg_avg =3D U32_MAX; + *agg_peak =3D max_t(u32, *agg_peak, peak_bw); =20 in->sum_avg =3D *agg_avg; --=20 2.52.0