race_on_read.cpp
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// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
#include "test.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
int fd;
char buf;
void *Thread1(void *x) {
barrier_wait(&barrier);
read(fd, &buf, 1);
return NULL;
}
void *Thread2(void *x) {
read(fd, &buf, 1);
barrier_wait(&barrier);
return NULL;
}
int main() {
barrier_init(&barrier, 2);
fd = open("/dev/random", O_RDONLY);
if (fd < 0) {
fprintf(stderr, "failed to open /dev/random (%d)\n", errno);
return 1;
}
pthread_t t[2];
pthread_create(&t[0], NULL, Thread1, NULL);
pthread_create(&t[1], NULL, Thread2, NULL);
pthread_join(t[0], NULL);
pthread_join(t[1], NULL);
close(fd);
fprintf(stderr, "DONE\n");
}
// CHECK: WARNING: ThreadSanitizer: data race
// CHECK: Write of size 1
// CHECK: #0 read
// CHECK: Previous write of size 1
// CHECK: #0 read
// CHECK: DONE