Patch "hwmon: (g762) Fix overflows and crash seen when writing limit attributes" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

hwmon: (g762) Fix overflows and crash seen when writing limit attributes

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
hwmon-g762-fix-overflows-and-crash-seen-when-writing-limit-attributes.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Guenter Roeck <[email protected]>
Date: Sun, 11 Dec 2016 13:27:42 -0800
Subject: hwmon: (g762) Fix overflows and crash seen when writing limit attributes

From: Guenter Roeck <[email protected]>

commit 4fccd4a1e8944033bcd7693ea4e8fb478cd2059a upstream.

Fix overflows seen when writing into fan speed limit attributes. Also fix crash due to division by zero, seen when certain very large values (such as 2147483648, or 0x80000000) are written into fan speed limit attributes.

---
 drivers/hwmon/g762.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

@@ -193,14 +193,17 @@ static inline unsigned int rpm_from_cnt(
  * Convert fan RPM value from sysfs into count value for fan controller
  * register (FAN_SET_CNT).
  */
-static inline unsigned char cnt_from_rpm(u32 rpm, u32 clk_freq, u16 p,
+static inline unsigned char cnt_from_rpm(unsigned long rpm, u32 clk_freq, u16 p,
 					 u8 clk_div, u8 gear_mult)
 {
-	if (!rpm)         /* to stop the fan, set cnt to 255 */
+	unsigned long f1 = clk_freq * 30 * gear_mult;
+	unsigned long f2 = p * clk_div;
+
+	if (!rpm)	/* to stop the fan, set cnt to 255 */
 		return 0xff;
 
-	return clamp_val(((clk_freq * 30 * gear_mult) / (rpm * p * clk_div)),
-			 0, 255);
+	rpm = clamp_val(rpm, f1 / (255 * f2), ULONG_MAX / f2);
+	return DIV_ROUND_CLOSEST(f1, rpm * f2);
 }
 
 /* helper to grab and cache data, at most one time per second */

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/hwmon-ds620-fix-overflows-seen-when-writing-temperature-limits.patch queue-4.4/hwmon-amc6821-sign-extension-temperature.patch queue-4.4/hwmon-scpi-fix-module-autoload.patch queue-4.4/hwmon-nct7802-fix-overflows-seen-when-writing-into-limit-attributes.patch queue-4.4/cris-only-build-flash-rescue-image-if-config_etrax_axisflashmap-is-selected.patch queue-4.4/hwmon-g762-fix-overflows-and-crash-seen-when-writing-limit-attributes.patch