[PATCH 3.13 122/187] hwmon: (lm78) Fix overflow problems seen when writing large temperature limits

Kamal Mostafa kamal at canonical.com
Mon Sep 15 22:08:52 UTC 2014


3.13.11.7 -stable review patch.  If anyone has any objections, please let me know.

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

From: Guenter Roeck <linux at roeck-us.net>

commit 1074d683a51f1aded3562add9ef313e75d557327 upstream.

On platforms with sizeof(int) < sizeof(long), writing a temperature
limit larger than MAXINT will result in unpredictable limit values
written to the chip. Avoid auto-conversion from long to int to fix
the problem.

Cc: Axel Lin <axel.lin at ingics.com>
Reviewed-by: Axel Lin <axel.lin at ingics.com>
Signed-off-by: Guenter Roeck <linux at roeck-us.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/hwmon/lm78.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/lm78.c b/drivers/hwmon/lm78.c
index a2f3b4a..b879427 100644
--- a/drivers/hwmon/lm78.c
+++ b/drivers/hwmon/lm78.c
@@ -108,7 +108,7 @@ static inline int FAN_FROM_REG(u8 val, int div)
  * TEMP: mC (-128C to +127C)
  * REG: 1C/bit, two's complement
  */
-static inline s8 TEMP_TO_REG(int val)
+static inline s8 TEMP_TO_REG(long val)
 {
 	int nval = clamp_val(val, -128000, 127000) ;
 	return nval < 0 ? (nval - 500) / 1000 : (nval + 500) / 1000;
-- 
1.9.1





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