1// Test ASan detection of stack-overflow condition when Linux sends SIGBUS.
2
3// RUN: %clangxx_asan -O0 %s -o %t && %env_asan_opts=use_sigaltstack=1 not %run %t 2>&1 | FileCheck %s
4
5#include <assert.h>
6#include <stdio.h>
7#include <stdlib.h>
8#include <string.h>
9#include <unistd.h>
10#include <sys/mman.h>
11#include <sys/resource.h>
12
13const int BS = 1024;
14volatile char x;
15volatile int y = 1;
16
17void recursive_func(char *p) {
18  char buf[BS];
19  buf[rand() % BS] = 1;
20  buf[rand() % BS] = 2;
21  x = buf[rand() % BS];
22  if (y)
23    recursive_func(buf);
24  x = 1; // prevent tail call optimization
25  // CHECK: {{stack-overflow on address 0x.* \(pc 0x.* bp 0x.* sp 0x.* T.*\)}}
26}
27
28void LimitStackAndReexec(int argc, char **argv) {
29  struct rlimit rlim;
30  int res = getrlimit(RLIMIT_STACK, &rlim);
31  assert(res == 0);
32  if (rlim.rlim_cur == RLIM_INFINITY) {
33    rlim.rlim_cur = 256 * 1024;
34    res = setrlimit(RLIMIT_STACK, &rlim);
35    assert(res == 0);
36
37    execv(argv[0], argv);
38    assert(0 && "unreachable");
39  }
40}
41
42int main(int argc, char **argv) {
43  LimitStackAndReexec(argc, argv);
44
45  // Map some memory just before the start of the current stack vma.
46  // When the stack grows down and crashes into it, Linux can send
47  // SIGBUS instead of SIGSEGV. See:
48  // http://lkml.iu.edu/hypermail/linux/kernel/1008.1/02299.html
49  const long pagesize = sysconf(_SC_PAGESIZE);
50  FILE *f = fopen("/proc/self/maps", "r");
51  char a[1000];
52  void *p = 0;
53  while (fgets(a, sizeof a, f)) {
54    if (strstr(a, "[stack]")) {
55      unsigned long addr;
56      if (sscanf(a, "%lx", &addr) == 1)
57        p = mmap((void *)(addr - 4 * pagesize), pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
58    }
59  }
60  assert(p);
61
62  recursive_func(0);
63  return 0;
64}
65