Commit 03cf7c47 authored May 06, 2011 by John Stultz

rtc: max8998: 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: John Stultz <john.stultz@linaro.org>

parent 2f5c4fe8

drivers/rtc/rtc-max8998.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -265,6 +265,8 @@ static int __devinit max8998_rtc_probe(struct platform_device *pdev)
		info->rtc = max8998->rtc;
		info->irq = max8998->irq_base + MAX8998_IRQ_ALARM0;

		platform_set_drvdata(pdev, info);

		info->rtc_dev = rtc_device_register("max8998-rtc", &pdev->dev,
		&max8998_rtc_ops, THIS_MODULE);

		@@ -274,8 +276,6 @@ static int __devinit max8998_rtc_probe(struct platform_device *pdev)
		goto out_rtc;
		}

		platform_set_drvdata(pdev, info);

		ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
		"rtc-alarm0", info);

		@@ -293,6 +293,7 @@ static int __devinit max8998_rtc_probe(struct platform_device *pdev)
		return 0;

		out_rtc:
		platform_set_drvdata(pdev, NULL);
		kfree(info);
		return ret;
		}