@@ -172,6 +172,8 @@ static int adm1266_gpio_get(struct gpio_chip *chip, unsigned int offset)
else
pmbus_cmd = ADM1266_PDIO_STATUS;
+ guard(pmbus_lock)(data->client);
+
ret = i2c_smbus_read_block_data(data->client, pmbus_cmd, read_buf);
if (ret < 0)
return ret;
@@ -194,6 +196,8 @@ static int adm1266_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask
unsigned int gpio_nr;
int ret;
+ guard(pmbus_lock)(data->client);
+
ret = i2c_smbus_read_block_data(data->client, ADM1266_GPIO_STATUS, read_buf);
if (ret < 0)
return ret;
@@ -235,6 +239,8 @@ static void adm1266_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
int ret;
int i;
+ guard(pmbus_lock)(data->client);
+
for (i = 0; i < ADM1266_GPIO_NR; i++) {
write_cmd = adm1266_gpio_mapping[i][1];
ret = adm1266_pmbus_block_xfer(data, ADM1266_GPIO_CONFIG, 1, &write_cmd, read_buf);
adm1266_gpio_get(), adm1266_gpio_get_multiple(), and adm1266_gpio_dbg_show() all issue PMBus reads against the device but none of them take pmbus_lock. The pmbus_core framework holds pmbus_lock around its own multi-transaction sequences (notably the "set PAGE, then read paged register" pattern used by hwmon attributes), so an unlocked GPIO accessor can land between a PAGE write and the subsequent paged read in another thread and corrupt either side's view of the device state machine. Take pmbus_lock at the top of each of the three accessors via the scope-based guard(). The lock is uncontended in the common case and adds only a single mutex round-trip per call. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai> Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> --- drivers/hwmon/pmbus/adm1266.c | 6 ++++++ 1 file changed, 6 insertions(+)