rtc: stmp3xxx: Initialize drvdata before registering device
Commit f44f7f96a20 ("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 device or platform drvdata.
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 drvdata is initialized prior to registering
the rtc device.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index ac40f97..90f05fe 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -176,6 +176,7 @@
free_irq(rtc_data->irq_alarm, &pdev->dev);
free_irq(rtc_data->irq_1msec, &pdev->dev);
rtc_device_unregister(rtc_data->rtc);
+ platform_set_drvdata(pdev, NULL);
iounmap(rtc_data->io);
kfree(rtc_data);
@@ -216,11 +217,14 @@
goto out_remap;
}
+ platform_set_drvdata(pdev, rtc_data);
+
mxs_reset_block(rtc_data->io);
__mxs_clrl(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0);
+
rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
&stmp3xxx_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc_data->rtc)) {
@@ -244,8 +248,6 @@
goto out_irq1;
}
- platform_set_drvdata(pdev, rtc_data);
-
return 0;
out_irq1:
@@ -256,6 +258,7 @@
rtc_data->io + STMP3XXX_RTC_CTRL);
rtc_device_unregister(rtc_data->rtc);
out_remap:
+ platform_set_drvdata(pdev, NULL);
iounmap(rtc_data->io);
out_free:
kfree(rtc_data);