tools/lib/lockdep/tests/ABBA_2threads.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <stdio.h>
   3 #include <pthread.h>
   4
   5 pthread_mutex_t a = PTHREAD_MUTEX_INITIALIZER;
   6 pthread_mutex_t b = PTHREAD_MUTEX_INITIALIZER;
   7 pthread_barrier_t bar;
   8
   9 void *ba_lock(void *arg)
  10 {
  11         int ret, i;
  12
  13         pthread_mutex_lock(&b);
  14
  15         if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD)
  16                 pthread_barrier_destroy(&bar);
  17
  18         pthread_mutex_lock(&a);
  19
  20         pthread_mutex_unlock(&a);
  21         pthread_mutex_unlock(&b);
  22 }
  23
  24 int main(void)
  25 {
  26         pthread_t t;
  27
  28         pthread_barrier_init(&bar, NULL, 2);
  29
  30         if (pthread_create(&t, NULL, ba_lock, NULL)) {
  31                 fprintf(stderr, "pthread_create() failed\n");
  32                 return 1;
  33         }
  34         pthread_mutex_lock(&a);
  35
  36         if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD)
  37                 pthread_barrier_destroy(&bar);
  38
  39         pthread_mutex_lock(&b);
  40
  41         pthread_mutex_unlock(&b);
  42         pthread_mutex_unlock(&a);
  43
  44         pthread_join(t, NULL);
  45
  46         return 0;
  47 }