rtc: m41t80: Initialize clientdata before registering device

Commit f44f7f96a2 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the clientdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the clientdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <[email protected]>
CC: Alessandro Zummo <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: [email protected]
Signed-off-by: John Stultz <[email protected]>
This commit is contained in:
John Stultz 2011-05-06 17:24:27 -07:00
commit a015dbc110

View file

@ -783,6 +783,9 @@ static int m41t80_probe(struct i2c_client *client,
goto exit;
}
clientdata->features = id->driver_data;
i2c_set_clientdata(client, clientdata);
rtc = rtc_device_register(client->name, &client->dev,
&m41t80_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
@ -792,8 +795,6 @@ static int m41t80_probe(struct i2c_client *client,
}
clientdata->rtc = rtc;
clientdata->features = id->driver_data;
i2c_set_clientdata(client, clientdata);
/* Make sure HT (Halt Update) bit is cleared */
rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);