From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 13296324B1F; Wed, 8 Apr 2026 18:23:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672634; cv=none; b=tX6ITGERkhGjERt0r9rKrpVhPzaEEcomhcidYm6kkXpUNN/d1Otft0KrriJq1T89pQjCa7lZlTpoN8IaR02PBSZ4e7rMijl73yG2D00LyffGpnVbtQlAfndv/dtcpQvEtyeBE+cZWm/cwEZUjWfrG3XiuZF38BP//HeIlFmvvhQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672634; c=relaxed/simple; bh=K8Y6W8TQV1F+afCMkP5aeA/Z51P4WUCgyoB7Hw+khdk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PrI3HmGU8WtcZiy+poQ6DV/5Z9E4Ny/3U1a1FQYMSi8C8CS/RB301VsnTo1u97fBMVIiBonPWhHUeHCA2bQXZ+4AYD9GYg6ewfoBFznc3/JPyj62w+dk0a0KGYOtq63HDe41IVWKTlHTR2TmXa2imSGO0qhcWf9D+elW8h7kulk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dI6o/8Ln; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dI6o/8Ln" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DD78C19421; Wed, 8 Apr 2026 18:23:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775672634; bh=K8Y6W8TQV1F+afCMkP5aeA/Z51P4WUCgyoB7Hw+khdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dI6o/8LnLe2+9tKJQDphksrvJZTZBZMrG5jVG4aHyTr79V0v5+pCS0HnpWWsIWj8J nDzKR8ssUCkcmABoS0f3XYkuBzUuxaGNfuUwjrlrKcFstbV9fwleHa7WEBzdQjXwN7 WAHFdgCBRmeSQ7aQ+kdHiT1eTrpBVAxlkvhrqnSo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sanman Pradhan , Guenter Roeck Subject: [PATCH 6.6 082/160] hwmon: (occ) Fix division by zero in occ_show_power_1() Date: Wed, 8 Apr 2026 20:02:49 +0200 Message-ID: <20260408175916.259248681@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175913.177092714@linuxfoundation.org> References: <20260408175913.177092714@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sanman Pradhan commit 39e2a5bf970402a8530a319cf06122e216ba57b8 upstream. In occ_show_power_1() case 1, the accumulator is divided by update_tag without checking for zero. If no samples have been collected yet (e.g. during early boot when the sensor block is included but hasn't been updated), update_tag is zero, causing a kernel divide-by-zero crash. The 2019 fix in commit 211186cae14d ("hwmon: (occ) Fix division by zero issue") only addressed occ_get_powr_avg() used by occ_show_power_2() and occ_show_power_a0(). This separate code path in occ_show_power_1() was missed. Fix this by reusing the existing occ_get_powr_avg() helper, which already handles the zero-sample case and uses mul_u64_u32_div() to multiply before dividing for better precision. Move the helper above occ_show_power_1() so it is visible at the call site. Fixes: c10e753d43eb ("hwmon (occ): Add sensor types and versions") Cc: stable@vger.kernel.org Signed-off-by: Sanman Pradhan Link: https://lore.kernel.org/r/20260326224510.294619-2-sanman.pradhan@hpe.com [groeck: Fix alignment problems reported by checkpatch] Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/occ/common.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) --- a/drivers/hwmon/occ/common.c +++ b/drivers/hwmon/occ/common.c @@ -420,6 +420,12 @@ static ssize_t occ_show_freq_2(struct de return sysfs_emit(buf, "%u\n", val); } +static u64 occ_get_powr_avg(u64 accum, u32 samples) +{ + return (samples == 0) ? 0 : + mul_u64_u32_div(accum, 1000000UL, samples); +} + static ssize_t occ_show_power_1(struct device *dev, struct device_attribute *attr, char *buf) { @@ -441,9 +447,8 @@ static ssize_t occ_show_power_1(struct d val = get_unaligned_be16(&power->sensor_id); break; case 1: - val = get_unaligned_be32(&power->accumulator) / - get_unaligned_be32(&power->update_tag); - val *= 1000000ULL; + val = occ_get_powr_avg(get_unaligned_be32(&power->accumulator), + get_unaligned_be32(&power->update_tag)); break; case 2: val = (u64)get_unaligned_be32(&power->update_tag) * @@ -459,12 +464,6 @@ static ssize_t occ_show_power_1(struct d return sysfs_emit(buf, "%llu\n", val); } -static u64 occ_get_powr_avg(u64 accum, u32 samples) -{ - return (samples == 0) ? 0 : - mul_u64_u32_div(accum, 1000000UL, samples); -} - static ssize_t occ_show_power_2(struct device *dev, struct device_attribute *attr, char *buf) {