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Commit 2f5c4fe8 authored by John Stultz's avatar John Stultz
Browse files

rtc: max8925: 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: 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: default avatarJohn Stultz <john.stultz@linaro.org>
parent a015dbc1

drivers/rtc/rtc-max8925.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -258,6 +258,8 @@ static int __devinit max8925_rtc_probe(struct platform_device *pdev) 
	}

	}





	dev_set_drvdata(&pdev->dev, info);

	dev_set_drvdata(&pdev->dev, info);

	/* XXX - isn't this redundant? */

	platform_set_drvdata(pdev, info);





	info->rtc_dev = rtc_device_register("max8925-rtc", &pdev->dev,

	info->rtc_dev = rtc_device_register("max8925-rtc", &pdev->dev,

					&max8925_rtc_ops, THIS_MODULE);

					&max8925_rtc_ops, THIS_MODULE);
@@ -267,10 +269,9 @@ static int __devinit max8925_rtc_probe(struct platform_device *pdev) 
		goto out_rtc;

		goto out_rtc;

	}

	}





	platform_set_drvdata(pdev, info);



	return 0;

	return 0;

out_rtc:

out_rtc:

	platform_set_drvdata(pdev, NULL);

	free_irq(chip->irq_base + MAX8925_IRQ_RTC_ALARM0, info);

	free_irq(chip->irq_base + MAX8925_IRQ_RTC_ALARM0, info);

out_irq:

out_irq:

	kfree(info);

	kfree(info);