nct6775: UBSAN: shift exponent 32 is too large for 32-bit type 'long unsigned int'
From: Paul Menzel
Date: Tue Jun 12 2018 - 17:50:54 EST
Dear Guenther, dear Jean,
Building Linux with the undefined behavior sanitizer (UBSAN), loading
the module *nct6775* on the ASRock E350M1 shows the error below.
```
[ 28.322775] UBSAN: Undefined behaviour in drivers/hwmon/nct6775.c:4179:27
[ 28.322833] shift exponent 32 is too large for 32-bit type 'long
unsigned int'
```
I believe this was introduced by commit cc66b3038254 (hwmon: (nct6775)
Rework temperature source and label handling), but the same issue was
already present before.
```
- for (i = 0; i < data->temp_label_num - 1; i++) {
+ for (i = 0; i < 32; i++) {
+ if (!(data->temp_mask & BIT(i + 1)))
+ continue;
```
`include/linux/bitops.h` has the macros below.
```
#define BIT(nr) (1UL << (nr))
#define BIT_ULL(nr) (1ULL << (nr))
```
Maybe `BIT_ULL` should be used, but I do not know, if thatâd would work
with `data->temp_mask`, which has type `u32`.
Kind regards,
Paul