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[134.84.121.28]) by smtp.gmail.com with ESMTPSA id m37sm6723175iti.6.2018.12.21.11.01.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 21 Dec 2018 11:01:39 -0800 (PST) From: Kangjie Lu To: kjlu@umn.edu Cc: pakki001@umn.edu, Jean Delvare , Guenter Roeck , linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] hwmon: (lm80) fix a missing check of the status of SMBus read Date: Fri, 21 Dec 2018 13:01:33 -0600 Message-Id: <20181221190134.930-1-kjlu@umn.edu> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If lm80_read_value() fails, it returns a negative number instead of the correct read data. Therefore, we should avoid using the data if it fails. The fix checks if lm80_read_value() fails, and if so, returns with the error number. Signed-off-by: Kangjie Lu --- drivers/hwmon/lm80.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c index 08e3945a6fbf..d91333557f04 100644 --- a/drivers/hwmon/lm80.c +++ b/drivers/hwmon/lm80.c @@ -360,6 +360,7 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, struct i2c_client *client = data->client; unsigned long min, val; u8 reg; + int rv; int err = kstrtoul(buf, 10, &val); if (err < 0) return err; @@ -390,8 +391,11 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, return -EINVAL; } - reg = (lm80_read_value(client, LM80_REG_FANDIV) & - ~(3 << (2 * (nr + 1)))) | (data->fan_div[nr] << (2 * (nr + 1))); + rv = lm80_read_value(client, LM80_REG_FANDIV); + if (rv < 0) + return rv; + reg = (rv & ~(3 << (2 * (nr + 1)))) + | (data->fan_div[nr] << (2 * (nr + 1))); lm80_write_value(client, LM80_REG_FANDIV, reg); /* Restore fan_min */ -- 2.17.1