helgrind/tests/free_is_write.c

   1
   2 #include <assert.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <pthread.h>
   6 #include <unistd.h>
   7
   8 static char* s_mem;
   9
  10 /* wait a second, so as to guarantee that the parent access
  11    the malloc'd area, then free it. */
  12 static void* thread_func(void* arg)
  13 {
  14     sleep(1);
  15     free(s_mem);
  16     return NULL;
  17 }
  18
  19 int main(int argc, char** argv)
  20 {
  21     pthread_t tid;
  22     int quiet;
  23
  24     fprintf(stderr, "Start.\n");
  25
  26     quiet = argc > 1;
  27
  28     s_mem = malloc(10);
  29     if (0 && !quiet)
  30         fprintf(stderr, "Pointer to allocated memory: %p\n", s_mem);
  31     assert(s_mem);
  32     pthread_create(&tid, NULL, thread_func, NULL);
  33
  34     /* Write, which isn't coordinated with the free ==> a race
  35        should be reported. */
  36     char c = s_mem[5];
  37     __asm__ __volatile__("" : : "r"((long)c) );
  38
  39     pthread_join(tid, NULL);
  40     fprintf(stderr, "Done.\n");
  41     return 0;
  42 }