Commit 73737b87 authored Mar 05, 2012 by Anatolij Gustschin Committed by Linus Torvalds Mar 05, 2012

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: Anatolij Gustschin <agust@denx.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus 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;
		}

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