1// RUN: %clangxx_tsan -O0 %s -o %t
2// RUN: not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-RACE
3// Test size larger than clear_shadow_mmap_threshold, which is handled differently.
4// RUN: not %run %t - 262144 2>&1 | FileCheck %s --check-prefix=CHECK-RACE
5// RUN: %run %t ignore 2>&1 | FileCheck %s --check-prefix=CHECK-IGNORE
6
7#include <sys/mman.h>
8#include <string.h>
9#include <assert.h>
10#include <atomic>
11
12#include "test.h"
13
14// Use atomic to ensure we do not have a race for the pointer value itself. We
15// only want to check races in the mmap'd memory to isolate the test that mmap
16// respects ignore annotations.
17std::atomic<int*> global_p;
18
19void mmap_ignored(bool ignore, size_t size) {
20 if (ignore) AnnotateIgnoreWritesBegin(__FILE__, __LINE__);
21 void *p =
22 mmap(addr: 0, len: size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, fd: -1, offset: 0);
23 if (ignore) AnnotateIgnoreWritesEnd(__FILE__, __LINE__);
24
25 // Use relaxed to retain the race between the mmap call and the memory write
26 global_p.store((int *)p, std::memory_order_relaxed);
27 barrier_wait(barrier: &barrier);
28}
29
30void *WriteToMemory(void *unused) {
31 barrier_wait(barrier: &barrier);
32 global_p[0] = 7;
33 return 0;
34}
35
36// Create race between allocating (mmap) and writing memory
37int main(int argc, const char *argv[]) {
38 bool ignore = (argc > 1) && (strcmp(s1: argv[1], s2: "ignore") == 0);
39 size_t size = argc > 2 ? atoi(nptr: argv[2]) : sysconf(_SC_PAGESIZE);
40
41 barrier_init(barrier: &barrier, count: 2);
42 pthread_t t;
43 pthread_create(newthread: &t, attr: 0, start_routine: WriteToMemory, arg: 0);
44 mmap_ignored(ignore, size);
45 pthread_join(th: t, thread_return: 0);
46
47 assert(global_p[0] == 7);
48 printf(format: "OK\n");
49 return 0;
50}
51
52// CHECK-RACE: WARNING: ThreadSanitizer: data race
53// CHECK-RACE: OK
54// CHECK-IGNORE-NOT: WARNING: ThreadSanitizer: data race
55// CHECK-IGNORE: OK
56

source code of compiler-rt/test/tsan/ignored-interceptors-mmap.cpp