Commit f4e708ae authored May 05, 2011 by Wolfram Sang Committed by John Stultz May 06, 2011

rtc: davinci: Initialize drvdata before registering device



Commit f44f7f96 ("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>

parent 5f54c8a0

drivers/rtc/rtc-davinci.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -524,6 +524,8 @@ static int __init davinci_rtc_probe(struct platform_device *pdev)
		goto fail2;
		}

		platform_set_drvdata(pdev, davinci_rtc);

		davinci_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
		&davinci_rtc_ops, THIS_MODULE);
		if (IS_ERR(davinci_rtc->rtc)) {
		@@ -553,8 +555,6 @@ static int __init davinci_rtc_probe(struct platform_device *pdev)

		rtcss_write(davinci_rtc, PRTCSS_RTC_CCTRL_CAEN, PRTCSS_RTC_CCTRL);

		platform_set_drvdata(pdev, davinci_rtc);

		device_init_wakeup(&pdev->dev, 0);

		return 0;
		@@ -562,6 +562,7 @@ static int __init davinci_rtc_probe(struct platform_device *pdev)
		fail4:
		rtc_device_unregister(davinci_rtc->rtc);
		fail3:
		platform_set_drvdata(pdev, NULL);
		iounmap(davinci_rtc->base);
		fail2:
		release_mem_region(davinci_rtc->pbase, davinci_rtc->base_size);