test/tsan/fd_stdout_race.cc

   1 // RUN: %clangxx_tsan -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8
   9 int X;
  10
  11 void *Thread1(void *x) {
  12   sleep(1);
  13   int f = open("/dev/random", O_RDONLY);
  14   char buf;
  15   read(f, &buf, 1);
  16   close(f);
  17   X = 42;
  18   return NULL;
  19 }
  20
  21 void *Thread2(void *x) {
  22   X = 43;
  23   write(STDOUT_FILENO, "a", 1);
  24   return NULL;
  25 }
  26
  27 int main() {
  28   pthread_t t[2];
  29   pthread_create(&t[0], NULL, Thread1, NULL);
  30   pthread_create(&t[1], NULL, Thread2, NULL);
  31   pthread_join(t[0], NULL);
  32   pthread_join(t[1], NULL);
  33 }
  34
  35 // CHECK: WARNING: ThreadSanitizer: data race
  36 // CHECK:   Write of size 4
  37 // CHECK:     #0 Thread1
  38 // CHECK:   Previous write of size 4
  39 // CHECK:     #0 Thread2
  40
  41