From 73737b878767ef441d7cc34ebeeba01dd0a68dd6 Mon Sep 17 00:00:00 2001 From: Anatolij Gustschin Date: Mon, 5 Mar 2012 14:59:16 -0800 Subject: [PATCH] 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 Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-r9701.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/rtc/rtc-r9701.c b/drivers/rtc/rtc-r9701.c index 9beba49c3c5b..2853c2a6f10f 100644 --- a/drivers/rtc/rtc-r9701.c +++ b/drivers/rtc/rtc-r9701.c @@ -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; } -- 2.20.1