hwmon: (pmbus_core) Fix Deadlock in pmbus_regulator_get_status

pmbus_regulator_get_status() acquires update_lock.
pmbus_regulator_get_error_flags() acquires it again, resulting in an
immediate deadlock.

Call _pmbus_get_flags() from pmbus_regulator_get_status() directly
to avoid the problem.

Reported-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Closes: https://lore.kernel.org/linux-hwmon/b7a3ad85-aab4-4718-a001-1d8b1c0eef36@roeck-us.net/T/#u
Cc: Naresh Solanki <Naresh.Solanki@9elements.com>
Cc: stable@vger.kernel.org # v6.2+
Fixes: c05f477c4ba3 ("hwmon: (pmbus/core) Implement regulator get_status")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 30aeb59..69a4e62 100644 (file)
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2946,6 +2946,7 @@ static int pmbus_regulator_get_status(struct regulator_dev *rdev)
        struct pmbus_data *data = i2c_get_clientdata(client);
        u8 page = rdev_get_id(rdev);
        int status, ret;
+       int event;
 
        mutex_lock(&data->update_lock);
        status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
@@ -2965,7 +2966,7 @@ static int pmbus_regulator_get_status(struct regulator_dev *rdev)
                goto unlock;
        }
 
-       ret = pmbus_regulator_get_error_flags(rdev, &status);
+       ret = _pmbus_get_flags(data, rdev_get_id(rdev), &status, &event, false);
        if (ret)
                goto unlock;