| From | Andi Kleen <> | Subject | [PATCH] [220/275] hwmon: (sht15) Fix integer overflow in humidity calculation | Date | Wed, 30 Mar 2011 14:07:45 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
commit ccd32e735de7a941906e093f8dca924bb05c5794 upstream.
An integer overflow occurs in the calculation of RHlinear when the relative humidity is greater than around 30%. The consequence is a subtle (but noticeable) error in the resulting humidity measurement.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com> Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/hwmon/sht15.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-2.6.35.y/drivers/hwmon/sht15.c =================================================================== --- linux-2.6.35.y.orig/drivers/hwmon/sht15.c 2011-03-29 22:50:29.011516087 -0700 +++ linux-2.6.35.y/drivers/hwmon/sht15.c 2011-03-29 23:03:02.824227904 -0700 @@ -333,11 +333,11 @@ const int c1 = -4; const int c2 = 40500; /* x 10 ^ -6 */ - const int c3 = -2800; /* x10 ^ -9 */ + const int c3 = -28; /* x 10 ^ -7 */ RHlinear = c1*1000 + c2 * data->val_humid/1000 - + (data->val_humid * data->val_humid * c3)/1000000; + + (data->val_humid * data->val_humid * c3) / 10000; return (temp - 25000) * (10000 + 80 * data->val_humid) / 1000000 + RHlinear; }
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