tree:   git://git.cmpxchg.org/linux-mmotm.git master
head:   c7d9284ee4a63d6419a16b75fe101bad8235b98b
commit: 5bcdae54ed7910798c2e284d4caab5f2115a92e8 [18/224] rtc: armada38x: fix concurrency access in armada38x_rtc_set_time
config: arm-allmodconfig (attached as .config)
reproduce:
  wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
  chmod +x ~/bin/make.cross
  git checkout 5bcdae54ed7910798c2e284d4caab5f2115a92e8
  # save the attached .config to linux build tree
  make.cross ARCH=arm 

All warnings:

   drivers/rtc/rtc-armada38x.c: In function 'armada38x_rtc_read_time':
>> drivers/rtc/rtc-armada38x.c:67:34: warning: unused variable 'flags' [-Wunused-variable]
     unsigned long time, time_check, flags;
                                     ^
   drivers/rtc/rtc-armada38x.c: In function 'armada38x_rtc_set_time':
>> drivers/rtc/rtc-armada38x.c:91:22: warning: unused variable 'flags' [-Wunused-variable]
     unsigned long time, flags;
                         ^

vim +/flags +67 drivers/rtc/rtc-armada38x.c

a3a42806 Gregory CLEMENT 2015-02-13  61  	udelay(5);
a3a42806 Gregory CLEMENT 2015-02-13  62  }
a3a42806 Gregory CLEMENT 2015-02-13  63  
a3a42806 Gregory CLEMENT 2015-02-13  64  static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
a3a42806 Gregory CLEMENT 2015-02-13  65  {
a3a42806 Gregory CLEMENT 2015-02-13  66  	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
a3a42806 Gregory CLEMENT 2015-02-13 @67  	unsigned long time, time_check, flags;
a3a42806 Gregory CLEMENT 2015-02-13  68  
5bcdae54 Gregory CLEMENT 2015-05-06  69  	mutex_lock(&rtc->mutex_time);
a3a42806 Gregory CLEMENT 2015-02-13  70  	time = readl(rtc->regs + RTC_TIME);
a3a42806 Gregory CLEMENT 2015-02-13  71  	/*
a3a42806 Gregory CLEMENT 2015-02-13  72  	 * WA for failing time set attempts. As stated in HW ERRATA if
a3a42806 Gregory CLEMENT 2015-02-13  73  	 * more than one second between two time reads is detected
a3a42806 Gregory CLEMENT 2015-02-13  74  	 * then read once again.
a3a42806 Gregory CLEMENT 2015-02-13  75  	 */
a3a42806 Gregory CLEMENT 2015-02-13  76  	time_check = readl(rtc->regs + RTC_TIME);
a3a42806 Gregory CLEMENT 2015-02-13  77  	if ((time_check - time) > 1)
a3a42806 Gregory CLEMENT 2015-02-13  78  		time_check = readl(rtc->regs + RTC_TIME);
a3a42806 Gregory CLEMENT 2015-02-13  79  
5bcdae54 Gregory CLEMENT 2015-05-06  80  	mutex_unlock(&rtc->mutex_time);
a3a42806 Gregory CLEMENT 2015-02-13  81  
a3a42806 Gregory CLEMENT 2015-02-13  82  	rtc_time_to_tm(time_check, tm);
a3a42806 Gregory CLEMENT 2015-02-13  83  
a3a42806 Gregory CLEMENT 2015-02-13  84  	return 0;
a3a42806 Gregory CLEMENT 2015-02-13  85  }
a3a42806 Gregory CLEMENT 2015-02-13  86  
a3a42806 Gregory CLEMENT 2015-02-13  87  static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
a3a42806 Gregory CLEMENT 2015-02-13  88  {
a3a42806 Gregory CLEMENT 2015-02-13  89  	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
a3a42806 Gregory CLEMENT 2015-02-13  90  	int ret = 0;
a3a42806 Gregory CLEMENT 2015-02-13 @91  	unsigned long time, flags;
a3a42806 Gregory CLEMENT 2015-02-13  92  
a3a42806 Gregory CLEMENT 2015-02-13  93  	ret = rtc_tm_to_time(tm, &time);
a3a42806 Gregory CLEMENT 2015-02-13  94  

:::::: The code at line 67 was first introduced by commit
:::::: a3a42806920ad12ec831fb2de4f63e251778300f drivers/rtc/rtc-armada38x: add a new RTC driver for recent mvebu SoCs

:::::: TO: Gregory CLEMENT <gregory.clement@free-electrons.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

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