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    Subject[PATCH 4.4 056/143] hwmon: (lm80) fix a missing check of the status of SMBus read
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    [ Upstream commit c9c63915519b1def7043b184680f33c24cd49d7b ]

    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 <kjlu@umn.edu>
    [groeck: One variable for return values is enough]
    Signed-off-by: Guenter Roeck <linux@roeck-us.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/hwmon/lm80.c | 15 ++++++++++-----
    1 file changed, 10 insertions(+), 5 deletions(-)

    diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c
    index 4bcd9b882948..47ddae6b7038 100644
    --- a/drivers/hwmon/lm80.c
    +++ b/drivers/hwmon/lm80.c
    @@ -360,9 +360,11 @@ 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 err = kstrtoul(buf, 10, &val);
    - if (err < 0)
    - return err;
    + int rv;
    +
    + rv = kstrtoul(buf, 10, &val);
    + if (rv < 0)
    + return rv;

    /* Save fan_min */
    mutex_lock(&data->update_lock);
    @@ -390,8 +392,11 @@ 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 */
    --
    2.19.1


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