1 // RUN: %clang_tsan -O1 %s -o %t && %env_tsan_opts=report_atomic_races=0 %run %t 2>&1 | FileCheck %s
2 // This test exposed non-atomicity in mmap interceptor
3 // which made shadow for the region temporarily unmapped.
4 // This resulted in crashes in the Accesser thread.
5 #include "test.h"
6 #include <errno.h>
7 #include <sys/mman.h>
8
9 // The size needs to be large enough to trigger
10 // large region optimization in the runtime.
11 const size_t kMmapSize = 16 << 20;
12
Remapper(void * arg)13 void *Remapper(void *arg) {
14 for (;;) {
15 void *p = mmap(arg, kMmapSize, PROT_READ | PROT_WRITE,
16 MAP_FIXED | MAP_PRIVATE | MAP_ANON, -1, 0);
17 if (p == MAP_FAILED)
18 exit(printf("mmap failed: %d\n", errno));
19 }
20 return 0;
21 }
22
Accesser(void * arg)23 void *Accesser(void *arg) {
24 unsigned rnd = time(0);
25 for (;;) {
26 int index = rand_r(&rnd) % kMmapSize;
27 char *p = &((char *)arg)[index];
28 __atomic_fetch_add(p, 1, __ATOMIC_ACQ_REL);
29 }
30 return 0;
31 }
32
main()33 int main() {
34 void *p = mmap(0, kMmapSize, PROT_READ | PROT_WRITE,
35 MAP_PRIVATE | MAP_ANON, -1, 0);
36 if (p == MAP_FAILED)
37 exit(printf("mmap failed: %d\n", errno));
38 pthread_attr_t attr;
39 pthread_attr_init(&attr);
40 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
41 pthread_t th[2];
42 if (pthread_create(&th[0], &attr, Remapper, p))
43 exit(printf("pthread_create failed: %d\n", errno));
44 if (pthread_create(&th[1], &attr, Accesser, p))
45 exit(printf("pthread_create failed: %d\n", errno));
46 pthread_attr_destroy(&attr);
47 sleep(3);
48 fprintf(stderr, "DONE\n");
49 }
50
51 // CHECK: DONE
52