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Commit 73737b87 authored by Anatolij Gustschin's avatar Anatolij Gustschin Committed by Linus Torvalds
Browse files

drivers/rtc/rtc-r9701.c: fix crash in r9701_remove() 



If probing the RTC didn't succeed due to failed RTC register access, the
RTC device will be unregistered.  Then, when removing the module
r9701_remove() causes a kernel crash while trying to unregister a not
registered RTC device.  Fix this by doing RTC register access test before
RTC device registration.

Signed-off-by: default avatarAnatolij Gustschin <agust@denx.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 22ea71d7

drivers/rtc/rtc-r9701.c

+7 −7
Original line number Diff line number Diff line
@@ -125,6 +125,13 @@ static int __devinit r9701_probe(struct spi_device *spi) 
	unsigned char tmp;

	int res;



	tmp = R100CNT;

	res = read_regs(&spi->dev, &tmp, 1);

	if (res || tmp != 0x20) {

		dev_err(&spi->dev, "cannot read RTC register\n");

		return -ENODEV;

	}



	rtc = rtc_device_register("r9701",

				&spi->dev, &r9701_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc))
@@ -132,13 +139,6 @@ static int __devinit r9701_probe(struct spi_device *spi) 


	dev_set_drvdata(&spi->dev, rtc);



	tmp = R100CNT;

	res = read_regs(&spi->dev, &tmp, 1);

	if (res || tmp != 0x20) {

		rtc_device_unregister(rtc);

		return res;

	}



	return 0;

}