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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 <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz 2011-05-06 17:24:27 -07:00
parent 9a281a677c
commit a015dbc110
1 changed files with 3 additions and 2 deletions
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5
drivers/rtc/rtc-m41t80.c
View File

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