Re: [PATCH 1/3] kcov: remove #ifdef CONFIG_RANDOMIZE_BASE

[kbuild test robot <lkp@intel.com>]

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Hi Andrey,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc1 next-20170921]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Andrey-Ryabinin/kcov-remove-ifdef-CONFIG_RANDOMIZE_BASE/20170922-035755
config: s390-allmodconfig (attached as .config)
compiler: s390x-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=s390 

All errors (new ones prefixed by >>):

   kernel/kcov.c: In function '__sanitizer_cov_trace_pc':
>> kernel/kcov.c:72:9: error: implicit declaration of function 'kaslr_offset' [-Werror=implicit-function-declaration]
      ip -= kaslr_offset();
            ^~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/kaslr_offset +72 kernel/kcov.c

5c9a8750 Dmitry Vyukov   2016-03-22  49  
5c9a8750 Dmitry Vyukov   2016-03-22  50  /*
5c9a8750 Dmitry Vyukov   2016-03-22  51   * Entry point from instrumented code.
5c9a8750 Dmitry Vyukov   2016-03-22  52   * This is called once per basic-block/edge.
5c9a8750 Dmitry Vyukov   2016-03-22  53   */
bdab42df James Morse     2016-04-28  54  void notrace __sanitizer_cov_trace_pc(void)
5c9a8750 Dmitry Vyukov   2016-03-22  55  {
5c9a8750 Dmitry Vyukov   2016-03-22  56  	struct task_struct *t;
5c9a8750 Dmitry Vyukov   2016-03-22  57  	enum kcov_mode mode;
5c9a8750 Dmitry Vyukov   2016-03-22  58  
5c9a8750 Dmitry Vyukov   2016-03-22  59  	t = current;
5c9a8750 Dmitry Vyukov   2016-03-22  60  	/*
5c9a8750 Dmitry Vyukov   2016-03-22  61  	 * We are interested in code coverage as a function of a syscall inputs,
5c9a8750 Dmitry Vyukov   2016-03-22  62  	 * so we ignore code executed in interrupts.
5c9a8750 Dmitry Vyukov   2016-03-22  63  	 */
f61e869d Dmitry Vyukov   2017-05-08  64  	if (!t || !in_task())
5c9a8750 Dmitry Vyukov   2016-03-22  65  		return;
5c9a8750 Dmitry Vyukov   2016-03-22  66  	mode = READ_ONCE(t->kcov_mode);
5c9a8750 Dmitry Vyukov   2016-03-22  67  	if (mode == KCOV_MODE_TRACE) {
5c9a8750 Dmitry Vyukov   2016-03-22  68  		unsigned long *area;
5c9a8750 Dmitry Vyukov   2016-03-22  69  		unsigned long pos;
4983f0ab Alexander Popov 2016-12-19  70  		unsigned long ip = _RET_IP_;
4983f0ab Alexander Popov 2016-12-19  71  
4983f0ab Alexander Popov 2016-12-19 @72  		ip -= kaslr_offset();
5c9a8750 Dmitry Vyukov   2016-03-22  73  
5c9a8750 Dmitry Vyukov   2016-03-22  74  		/*
5c9a8750 Dmitry Vyukov   2016-03-22  75  		 * There is some code that runs in interrupts but for which
5c9a8750 Dmitry Vyukov   2016-03-22  76  		 * in_interrupt() returns false (e.g. preempt_schedule_irq()).
5c9a8750 Dmitry Vyukov   2016-03-22  77  		 * READ_ONCE()/barrier() effectively provides load-acquire wrt
5c9a8750 Dmitry Vyukov   2016-03-22  78  		 * interrupts, there are paired barrier()/WRITE_ONCE() in
5c9a8750 Dmitry Vyukov   2016-03-22  79  		 * kcov_ioctl_locked().
5c9a8750 Dmitry Vyukov   2016-03-22  80  		 */
5c9a8750 Dmitry Vyukov   2016-03-22  81  		barrier();
5c9a8750 Dmitry Vyukov   2016-03-22  82  		area = t->kcov_area;
5c9a8750 Dmitry Vyukov   2016-03-22  83  		/* The first word is number of subsequent PCs. */
5c9a8750 Dmitry Vyukov   2016-03-22  84  		pos = READ_ONCE(area[0]) + 1;
5c9a8750 Dmitry Vyukov   2016-03-22  85  		if (likely(pos < t->kcov_size)) {
4983f0ab Alexander Popov 2016-12-19  86  			area[pos] = ip;
5c9a8750 Dmitry Vyukov   2016-03-22  87  			WRITE_ONCE(area[0], pos);
5c9a8750 Dmitry Vyukov   2016-03-22  88  		}
5c9a8750 Dmitry Vyukov   2016-03-22  89  	}
5c9a8750 Dmitry Vyukov   2016-03-22  90  }
5c9a8750 Dmitry Vyukov   2016-03-22  91  EXPORT_SYMBOL(__sanitizer_cov_trace_pc);
5c9a8750 Dmitry Vyukov   2016-03-22  92  

:::::: The code at line 72 was first introduced by commit
:::::: 4983f0ab7ffaad1e534b21975367429736475205 kcov: make kcov work properly with KASLR enabled

:::::: TO: Alexander Popov <alex.popov@linux.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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