diff options
| author | Sanman Pradhan <psanman@juniper.net> | 2026-03-26 22:45:23 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-11 14:29:42 +0200 |
| commit | 7b89ce0c98bf3015f493ca4285b2d1056cd8c733 (patch) | |
| tree | 87bae1baf24702f9f0d8223fab775460bc4834da | |
| parent | 37459f84cf22ff9f84c8589839ea1448e79295b5 (diff) | |
hwmon: (occ) Fix division by zero in occ_show_power_1()
commit 39e2a5bf970402a8530a319cf06122e216ba57b8 upstream.
In occ_show_power_1() case 1, the accumulator is divided by
update_tag without checking for zero. If no samples have been
collected yet (e.g. during early boot when the sensor block is
included but hasn't been updated), update_tag is zero, causing
a kernel divide-by-zero crash.
The 2019 fix in commit 211186cae14d ("hwmon: (occ) Fix division by
zero issue") only addressed occ_get_powr_avg() used by
occ_show_power_2() and occ_show_power_a0(). This separate code
path in occ_show_power_1() was missed.
Fix this by reusing the existing occ_get_powr_avg() helper, which
already handles the zero-sample case and uses mul_u64_u32_div()
to multiply before dividing for better precision. Move the helper
above occ_show_power_1() so it is visible at the call site.
Fixes: c10e753d43eb ("hwmon (occ): Add sensor types and versions")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://lore.kernel.org/r/20260326224510.294619-2-sanman.pradhan@hpe.com
[groeck: Fix alignment problems reported by checkpatch]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hwmon/occ/common.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c index 86c79156a46b..42cc6068bb08 100644 --- a/drivers/hwmon/occ/common.c +++ b/drivers/hwmon/occ/common.c @@ -420,6 +420,12 @@ static ssize_t occ_show_freq_2(struct device *dev, return sysfs_emit(buf, "%u\n", val); } +static u64 occ_get_powr_avg(u64 accum, u32 samples) +{ + return (samples == 0) ? 0 : + mul_u64_u32_div(accum, 1000000UL, samples); +} + static ssize_t occ_show_power_1(struct device *dev, struct device_attribute *attr, char *buf) { @@ -441,9 +447,8 @@ static ssize_t occ_show_power_1(struct device *dev, val = get_unaligned_be16(&power->sensor_id); break; case 1: - val = get_unaligned_be32(&power->accumulator) / - get_unaligned_be32(&power->update_tag); - val *= 1000000ULL; + val = occ_get_powr_avg(get_unaligned_be32(&power->accumulator), + get_unaligned_be32(&power->update_tag)); break; case 2: val = (u64)get_unaligned_be32(&power->update_tag) * @@ -459,12 +464,6 @@ static ssize_t occ_show_power_1(struct device *dev, return sysfs_emit(buf, "%llu\n", val); } -static u64 occ_get_powr_avg(u64 accum, u32 samples) -{ - return (samples == 0) ? 0 : - mul_u64_u32_div(accum, 1000000UL, samples); -} - static ssize_t occ_show_power_2(struct device *dev, struct device_attribute *attr, char *buf) { |