diff options
| author | Sanman Pradhan <psanman@juniper.net> | 2026-03-19 17:31:29 +0000 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2026-03-24 07:55:34 -0700 |
| commit | 3075a3951f7708da5a8ab47b0b7d068a32f69e58 (patch) | |
| tree | 0b2d38b6b4dcfcda820e107ea82b0489925e0f52 | |
| parent | f7e775c4694782844c66da5316fed82881835cf8 (diff) | |
hwmon: (pmbus/isl68137) Add mutex protection for AVS enable sysfs attributes
The custom avs0_enable and avs1_enable sysfs attributes access PMBus
registers through the exported API helpers (pmbus_read_byte_data,
pmbus_read_word_data, pmbus_write_word_data, pmbus_update_byte_data)
without holding the PMBus update_lock mutex. These exported helpers do
not acquire the mutex internally, unlike the core's internal callers
which hold the lock before invoking them.
The store callback is especially vulnerable: it performs a multi-step
read-modify-write sequence (read VOUT_COMMAND, write VOUT_COMMAND, then
update OPERATION) where concurrent access from another thread could
interleave and corrupt the register state.
Add pmbus_lock_interruptible()/pmbus_unlock() around both the show and
store callbacks to serialize PMBus register access with the rest of the
driver.
Fixes: 038a9c3d1e424 ("hwmon: (pmbus/isl68137) Add driver for Intersil ISL68137 PWM Controller")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://lore.kernel.org/r/20260319173055.125271-3-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/pmbus/isl68137.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/drivers/hwmon/pmbus/isl68137.c b/drivers/hwmon/pmbus/isl68137.c index e7dac26b5be6..3e3a887aad05 100644 --- a/drivers/hwmon/pmbus/isl68137.c +++ b/drivers/hwmon/pmbus/isl68137.c @@ -96,7 +96,15 @@ static ssize_t isl68137_avs_enable_show_page(struct i2c_client *client, int page, char *buf) { - int val = pmbus_read_byte_data(client, page, PMBUS_OPERATION); + int val; + + val = pmbus_lock_interruptible(client); + if (val) + return val; + + val = pmbus_read_byte_data(client, page, PMBUS_OPERATION); + + pmbus_unlock(client); if (val < 0) return val; @@ -118,6 +126,10 @@ static ssize_t isl68137_avs_enable_store_page(struct i2c_client *client, op_val = result ? ISL68137_VOUT_AVS : 0; + rc = pmbus_lock_interruptible(client); + if (rc) + return rc; + /* * Writes to VOUT setpoint over AVSBus will persist after the VRM is * switched to PMBus control. Switching back to AVSBus control @@ -129,17 +141,20 @@ static ssize_t isl68137_avs_enable_store_page(struct i2c_client *client, rc = pmbus_read_word_data(client, page, 0xff, PMBUS_VOUT_COMMAND); if (rc < 0) - return rc; + goto unlock; rc = pmbus_write_word_data(client, page, PMBUS_VOUT_COMMAND, rc); if (rc < 0) - return rc; + goto unlock; } rc = pmbus_update_byte_data(client, page, PMBUS_OPERATION, ISL68137_VOUT_AVS, op_val); +unlock: + pmbus_unlock(client); + return (rc < 0) ? rc : count; } |