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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Kangjie Lu <kjlu@umn.edu>, Guenter Roeck <linux@roeck-us.net>,
	Sasha Levin <sashal@kernel.org>,
	linux-hwmon@vger.kernel.org
Subject: [PATCH AUTOSEL 4.20 263/304] hwmon: (lm80) fix a missing check of the status of SMBus read
Date: Mon, 28 Jan 2019 10:43:00 -0500
Message-ID: <20190128154341.47195-263-sashal@kernel.org> (raw)
In-Reply-To: <20190128154341.47195-1-sashal@kernel.org>

From: Kangjie Lu <kjlu@umn.edu>

[ 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 08e3945a6fbf..04f9df0d2341 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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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190128154341.47195-1-sashal@kernel.org>
2019-01-28 15:43 ` Sasha Levin [this message]
2019-01-28 15:43 ` [PATCH AUTOSEL 4.20 264/304] hwmon: (lm80) fix a missing check of bus read in lm80 probe Sasha Levin

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