[peterz-queue:locking/core 10/18] kernel/locking/osq_lock.c:78:7: error: implicit declaration of function 'data_race'

[peterz-queue:locking/core 10/18] kernel/locking/osq_lock.c:78:7: error: implicit declaration of function 'data_race'

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3213 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git locking/core
head:   3632aa63d7b6bf773a5ba00e06415a144ffd25d1
commit: 6bf619166f87b59e2bffc68f34f2b2056bb2483c [10/18] locking/osq_lock: mark an intentional data race
config: arc-defconfig (attached as .config)
compiler: arc-elf-gcc (GCC) 9.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 6bf619166f87b59e2bffc68f34f2b2056bb2483c
        # save the attached .config to linux build tree
        GCC_VERSION=9.2.0 make.cross ARCH=arc 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   kernel/locking/osq_lock.c: In function 'osq_wait_next':
>> kernel/locking/osq_lock.c:78:7: error: implicit declaration of function 'data_race' [-Werror=implicit-function-declaration]
      78 |   if (data_race(node->next)) {
         |       ^~~~~~~~~
   cc1: some warnings being treated as errors

vim +/data_race +78 kernel/locking/osq_lock.c

    36	
    37	/*
    38	 * Get a stable @node->next pointer, either for unlock() or unqueue() purposes.
    39	 * Can return NULL in case we were the last queued and we updated @lock instead.
    40	 */
    41	static inline struct optimistic_spin_node *
    42	osq_wait_next(struct optimistic_spin_queue *lock,
    43		      struct optimistic_spin_node *node,
    44		      struct optimistic_spin_node *prev)
    45	{
    46		struct optimistic_spin_node *next = NULL;
    47		int curr = encode_cpu(smp_processor_id());
    48		int old;
    49	
    50		/*
    51		 * If there is a prev node in queue, then the 'old' value will be
    52		 * the prev node's CPU #, else it's set to OSQ_UNLOCKED_VAL since if
    53		 * we're currently last in queue, then the queue will then become empty.
    54		 */
    55		old = prev ? prev->cpu : OSQ_UNLOCKED_VAL;
    56	
    57		for (;;) {
    58			if (atomic_read(&lock->tail) == curr &&
    59			    atomic_cmpxchg_acquire(&lock->tail, curr, old) == curr) {
    60				/*
    61				 * We were the last queued, we moved @lock back. @prev
    62				 * will now observe @lock and will complete its
    63				 * unlock()/unqueue().
    64				 */
    65				break;
    66			}
    67	
    68			/*
    69			 * We must xchg() the @node->next value, because if we were to
    70			 * leave it in, a concurrent unlock()/unqueue() from
    71			 * @node->next might complete Step-A and think its @prev is
    72			 * still valid.
    73			 *
    74			 * If the concurrent unlock()/unqueue() wins the race, we'll
    75			 * wait for either @lock to point to us, through its Step-B, or
    76			 * wait for a new @node->next from its Step-C.
    77			 */
  > 78			if (data_race(node->next)) {
    79				next = xchg(&node->next, NULL);
    80				if (next)
    81					break;
    82			}
    83	
    84			cpu_relax();
    85		}
    86	
    87		return next;
    88	}
    89	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 9129 bytes --]