Commit 5f54c8a0 authored May 04, 2011 by Wolfram Sang Committed by John Stultz May 06, 2011

rtc: mxc: 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 5895198c

drivers/rtc/rtc-mxc.c

+11 −8

Original line number	Diff line number	Diff line
		@@ -418,14 +418,6 @@ static int __init mxc_rtc_probe(struct platform_device *pdev)
		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);

		/* Configure and enable the RTC */
		@@ -438,8 +430,19 @@ static int __init mxc_rtc_probe(struct platform_device *pdev)
		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;

		exit_clr_drvdata:
		platform_set_drvdata(pdev, NULL);
		exit_put_clk:
		clk_disable(pdata->clk);
		clk_put(pdata->clk);