Commit 91bb8f45 authored Jun 12, 2018 by Guenter Roeck

hwmon: (nct6775) Fix loop limit



Commit cc66b303 ("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: cc66b303 ("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>

parent 536e0019

drivers/hwmon/nct6775.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -4175,7 +4175,7 @@ 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])

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