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hwmon: (nct6775) Fix loop limit

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[ Upstream commit 91bb8f45f73f19a0150c233c0f11cdeb6d71d1e9 ]

Commit cc66b3038254 ("hwmon: (nct6775) Rework temperature source and label
handling") changed a loop limit from "data->temp_label_num - 1" to "32",
as part of moving from a string array to a bit mask. This results in the
following error, reported by UBSAN.

UBSAN: Undefined behaviour in drivers/hwmon/nct6775.c:4179:27
shift exponent 32 is too large for 32-bit type 'long unsigned int'

Similar to the original loop, the limit has to be one less than the
number of bits.

Fixes: cc66b3038254 ("hwmon: (nct6775) Rework temperature source and label handling")
Reported-by: Paul Menzel <pmenzel+linux-hwmon@molgen.mpg.de>
Cc: Paul Menzel <pmenzel+linux-hwmon@molgen.mpg.de>
Tested-by: Paul Menzel <pmenzel+linux-hwmon@molgen.mpg.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Guenter Roeck 2018-06-12 15:19:35 -07:00 committed by Greg Kroah-Hartman
parent c0f29f9d8a
commit 4dff89e722
1 changed files with 1 additions and 1 deletions
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2
drivers/hwmon/nct6775.c
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@ -4107,7 +4107,7 @@ static int nct6775_probe(struct platform_device *pdev)
* The temperature is already monitored if the respective bit in <mask>
* is set.
*/
for (i = 0; i < 32; i++) {
for (i = 0; i < 31; i++) {
if (!(data->temp_mask & BIT(i + 1)))
continue;
if (!reg_temp_alternate[i])