From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D2E7C072A2 for ; Wed, 15 Nov 2023 19:31:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234077AbjKOTby (ORCPT ); Wed, 15 Nov 2023 14:31:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234090AbjKOTbw (ORCPT ); Wed, 15 Nov 2023 14:31:52 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD9FE12C for ; Wed, 15 Nov 2023 11:31:48 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5287BC433C9; Wed, 15 Nov 2023 19:31:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700076708; bh=0I0ZPZrK+yqL4IQoCuZ6vg9pwTckVAX+ujSpocYxKdU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lDEwml1sgC7veC8en5IJuPdAsfZ+GWGM2Y0g/6SktbYCruZXPJGzuOuBLlB4kDTFY sq3MV76IKiYSiib9IXIyFF9FhukgDidfd1j8P3rzcQAnTCKEgcBDMPKndwdCwFwEfM 53NLup48usHuwnhRZVAnSV1mMkyuLADKk2J6xx/0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zev Weiss , Thomas Zajic , Guenter Roeck Subject: [PATCH 6.6 001/603] hwmon: (nct6775) Fix incorrect variable reuse in fan_div calculation Date: Wed, 15 Nov 2023 14:09:06 -0500 Message-ID: <20231115191613.210810188@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115191613.097702445@linuxfoundation.org> References: <20231115191613.097702445@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zev Weiss commit 920057ad521dc8669e534736c2a12c14ec9fb2d7 upstream. In the regmap conversion in commit 4ef2774511dc ("hwmon: (nct6775) Convert register access to regmap API") I reused the 'reg' variable for all three register reads in the fan speed calculation loop in nct6775_update_device(), but failed to notice that the value from the first one (data->REG_FAN[i]) is actually used in the call to nct6775_select_fan_div() at the end of the loop body. Since that patch the register value passed to nct6775_select_fan_div() has been (conditionally) incorrectly clobbered with the value of a different register than intended, which has in at least some cases resulted in fan speeds being adjusted down to zero. Fix this by using dedicated temporaries for the two intermediate register reads instead of 'reg'. Signed-off-by: Zev Weiss Fixes: 4ef2774511dc ("hwmon: (nct6775) Convert register access to regmap API") Reported-by: Thomas Zajic Tested-by: Thomas Zajic Cc: stable@vger.kernel.org # v5.19+ Link: https://lore.kernel.org/r/20230929200822.964-2-zev@bewilderbeest.net Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/nct6775-core.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/drivers/hwmon/nct6775-core.c +++ b/drivers/hwmon/nct6775-core.c @@ -1614,17 +1614,21 @@ struct nct6775_data *nct6775_update_devi data->fan_div[i]); if (data->has_fan_min & BIT(i)) { - err = nct6775_read_value(data, data->REG_FAN_MIN[i], ®); + u16 tmp; + + err = nct6775_read_value(data, data->REG_FAN_MIN[i], &tmp); if (err) goto out; - data->fan_min[i] = reg; + data->fan_min[i] = tmp; } if (data->REG_FAN_PULSES[i]) { - err = nct6775_read_value(data, data->REG_FAN_PULSES[i], ®); + u16 tmp; + + err = nct6775_read_value(data, data->REG_FAN_PULSES[i], &tmp); if (err) goto out; - data->fan_pulses[i] = (reg >> data->FAN_PULSE_SHIFT[i]) & 0x03; + data->fan_pulses[i] = (tmp >> data->FAN_PULSE_SHIFT[i]) & 0x03; } err = nct6775_select_fan_div(dev, data, i, reg);