diff options
| author | David Lechner <dlechner@baylibre.com> | 2025-01-15 14:48:27 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-01-23 17:22:54 +0100 |
| commit | eed792d9894c0e1c83f8c008d2613d98f8e5348b (patch) | |
| tree | fcc4f7661784c220a33924d878e06720d7a3be84 | |
| parent | 9e2d61c4dcd8adf5755a6a7106476993926fc225 (diff) | |
hwmon: (ltc2991) Fix mixed signed/unsigned in DIV_ROUND_CLOSEST
[ Upstream commit e9b24deb84863c5a77dda5be57b6cb5bf4127b85 ]
Fix use of DIV_ROUND_CLOSEST where a possibly negative value is divided
by an unsigned type by casting the unsigned type to the signed type of
the same size (st->r_sense_uohm[channel] has type of u32).
The docs on the DIV_ROUND_CLOSEST macro explain that dividing a negative
value by an unsigned type is undefined behavior. The actual behavior is
that it converts both values to unsigned before doing the division, for
example:
int ret = DIV_ROUND_CLOSEST(-100, 3U);
results in ret == 1431655732 instead of -33.
Fixes: 2b9ea4262ae9 ("hwmon: Add driver for ltc2991")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20250115-hwmon-ltc2991-fix-div-round-closest-v1-1-b4929667e457@baylibre.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/hwmon/ltc2991.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/hwmon/ltc2991.c b/drivers/hwmon/ltc2991.c index 7ca139e4b6af..6d5d4cb846da 100644 --- a/drivers/hwmon/ltc2991.c +++ b/drivers/hwmon/ltc2991.c @@ -125,7 +125,7 @@ static int ltc2991_get_curr(struct ltc2991_state *st, u32 reg, int channel, /* Vx-Vy, 19.075uV/LSB */ *val = DIV_ROUND_CLOSEST(sign_extend32(reg_val, 14) * 19075, - st->r_sense_uohm[channel]); + (s32)st->r_sense_uohm[channel]); return 0; } |