compiler-rt/test/tsan/race_on_read.cpp

   1 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
   2 #include "test.h"
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <fcntl.h>
   6 #include <errno.h>
   7
   8 int fd;
   9 char buf;
  10
  11 void *Thread1(void *x) {
  12   barrier_wait(&barrier);
  13   read(fd, &buf, 1);
  14   return NULL;
  15 }
  16
  17 void *Thread2(void *x) {
  18   read(fd, &buf, 1);
  19   barrier_wait(&barrier);
  20   return NULL;
  21 }
  22
  23 int main() {
  24   barrier_init(&barrier, 2);
  25   fd = open("/dev/random", O_RDONLY);
  26   if (fd < 0) {
  27     fprintf(stderr, "failed to open /dev/random (%d)\n", errno);
  28     return 1;
  29   }
  30   pthread_t t[2];
  31   pthread_create(&t[0], NULL, Thread1, NULL);
  32   pthread_create(&t[1], NULL, Thread2, NULL);
  33   pthread_join(t[0], NULL);
  34   pthread_join(t[1], NULL);
  35   close(fd);
  36   fprintf(stderr, "DONE\n");
  37 }
  38
  39 // CHECK: WARNING: ThreadSanitizer: data race
  40 // CHECK:   Write of size 1
  41 // CHECK:     #0 read
  42 // CHECK:   Previous write of size 1
  43 // CHECK:     #0 read
  44 // CHECK: DONE
  45