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rtc: mxc: Initialize drvdata 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 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.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
[fixed up commit log -jstultz]
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Wolfram Sang 2011-05-04 17:31:27 +02:00 committed by John Stultz
parent 5895198c56
commit 5f54c8a00a
1 changed files with 11 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/rtc/rtc-mxc.c
View File

@ -418,14 +418,6 @@ static int __init mxc_rtc_probe(struct platform_device *pdev)
goto exit_put_clk; goto exit_put_clk;
} }
rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc);
goto exit_put_clk;
}
pdata->rtc = rtc;
platform_set_drvdata(pdev, pdata); platform_set_drvdata(pdev, pdata);
/* Configure and enable the RTC */ /* Configure and enable the RTC */
@ -438,8 +430,19 @@ static int __init mxc_rtc_probe(struct platform_device *pdev)
pdata->irq = -1; pdata->irq = -1;
} }
rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc);
goto exit_clr_drvdata;
}
pdata->rtc = rtc;
return 0; return 0;
exit_clr_drvdata:
platform_set_drvdata(pdev, NULL);
exit_put_clk: exit_put_clk:
clk_disable(pdata->clk); clk_disable(pdata->clk);
clk_put(pdata->clk); clk_put(pdata->clk);