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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>
This commit is contained in:
Anatolij Gustschin 2012-03-05 14:59:16 -08:00 committed by Linus Torvalds
parent 22ea71d7f4
commit 73737b8787
1 changed files with 7 additions and 7 deletions
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14
drivers/rtc/rtc-r9701.c
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@ -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;
}