// https://syzkaller.appspot.com/bug?id=af3a0728c8cbf6903ec2b0836441287cced00c1c
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/if_arp.h>
#include <pthread.h>
#include <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}
#include <errno.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <string.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

static void fail(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
  uintptr_t addr = (uintptr_t)info->si_addr;
  const uintptr_t prog_start = 1 << 20;
  const uintptr_t prog_end = 100 << 20;
  if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) &&
      (addr < prog_start || addr > prog_end)) {
    _longjmp(segv_env, 1);
  }
  doexit(sig);
}

static void install_segv_handler()
{
  struct sigaction sa;

  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
  syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);

  memset(&sa, 0, sizeof(sa));
  sa.sa_sigaction = segv_handler;
  sa.sa_flags = SA_NODEFER | SA_SIGINFO;
  sigaction(SIGSEGV, &sa, NULL);
  sigaction(SIGBUS, &sa, NULL);
}

#define NONFAILING(...)                                                        \
  {                                                                            \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    if (_setjmp(segv_env) == 0) {                                              \
      __VA_ARGS__;                                                             \
    }                                                                          \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
  }

static void vsnprintf_check(char* str, size_t size, const char* format,
                            va_list args)
{
  int rv;

  rv = vsnprintf(str, size, format, args);
  if (rv < 0)
    fail("tun: snprintf failed");
  if ((size_t)rv >= size)
    fail("tun: string '%s...' doesn't fit into buffer", str);
}

#define COMMAND_MAX_LEN 128
#define PATH_PREFIX                                                            \
  "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin "
#define PATH_PREFIX_LEN (sizeof(PATH_PREFIX) - 1)

static void execute_command(bool panic, const char* format, ...)
{
  va_list args;
  char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN];
  int rv;

  va_start(args, format);
  memcpy(command, PATH_PREFIX, PATH_PREFIX_LEN);
  vsnprintf_check(command + PATH_PREFIX_LEN, COMMAND_MAX_LEN, format, args);
  va_end(args);
  rv = system(command);
  if (rv) {
    if (panic)
      fail("command '%s' failed: %d", &command[0], rv);
  }
}

static int tunfd = -1;
static int tun_frags_enabled;

#define SYZ_TUN_MAX_PACKET_SIZE 1000

#define TUN_IFACE "syz_tun"

#define LOCAL_MAC "aa:aa:aa:aa:aa:aa"
#define REMOTE_MAC "aa:aa:aa:aa:aa:bb"

#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"

#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"

#define IFF_NAPI 0x0010
#define IFF_NAPI_FRAGS 0x0020

static void initialize_tun(void)
{
  tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
  if (tunfd == -1) {
    printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
    printf("otherwise fuzzing or reproducing might not work as intended\n");
    return;
  }
  const int kTunFd = 252;
  if (dup2(tunfd, kTunFd) < 0)
    fail("dup2(tunfd, kTunFd) failed");
  close(tunfd);
  tunfd = kTunFd;

  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
  ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS;
  if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0)
      fail("tun: ioctl(TUNSETIFF) failed");
  }
  if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0)
    fail("tun: ioctl(TUNGETIFF) failed");
  tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0;

  execute_command(0, "sysctl -w net.ipv6.conf.%s.accept_dad=0", TUN_IFACE);

  execute_command(0, "sysctl -w net.ipv6.conf.%s.router_solicitations=0",
                  TUN_IFACE);

  execute_command(1, "ip link set dev %s address %s", TUN_IFACE, LOCAL_MAC);
  execute_command(1, "ip addr add %s/24 dev %s", LOCAL_IPV4, TUN_IFACE);
  execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV4, REMOTE_MAC, TUN_IFACE);
  execute_command(0, "ip -6 addr add %s/120 dev %s", LOCAL_IPV6, TUN_IFACE);
  execute_command(0, "ip -6 neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV6, REMOTE_MAC, TUN_IFACE);
  execute_command(1, "ip link set dev %s up", TUN_IFACE);
}

#define DEV_IPV4 "172.20.20.%d"
#define DEV_IPV6 "fe80::%02hx"
#define DEV_MAC "aa:aa:aa:aa:aa:%02hx"

static void snprintf_check(char* str, size_t size, const char* format, ...)
{
  va_list args;

  va_start(args, format);
  vsnprintf_check(str, size, format, args);
  va_end(args);
}

static void initialize_netdevices(void)
{
  unsigned i;
  const char* devtypes[] = {"ip6gretap", "bridge", "vcan", "bond", "team"};
  const char* devnames[] = {"lo",
                            "sit0",
                            "bridge0",
                            "vcan0",
                            "tunl0",
                            "gre0",
                            "gretap0",
                            "ip_vti0",
                            "ip6_vti0",
                            "ip6tnl0",
                            "ip6gre0",
                            "ip6gretap0",
                            "erspan0",
                            "bond0",
                            "veth0",
                            "veth1",
                            "team0",
                            "veth0_to_bridge",
                            "veth1_to_bridge",
                            "veth0_to_bond",
                            "veth1_to_bond",
                            "veth0_to_team",
                            "veth1_to_team"};
  const char* devmasters[] = {"bridge", "bond", "team"};

  for (i = 0; i < sizeof(devtypes) / (sizeof(devtypes[0])); i++)
    execute_command(0, "ip link add dev %s0 type %s", devtypes[i], devtypes[i]);
  execute_command(0, "ip link add type veth");

  for (i = 0; i < sizeof(devmasters) / (sizeof(devmasters[0])); i++) {
    execute_command(
        0, "ip link add name %s_slave_0 type veth peer name veth0_to_%s",
        devmasters[i], devmasters[i]);
    execute_command(
        0, "ip link add name %s_slave_1 type veth peer name veth1_to_%s",
        devmasters[i], devmasters[i]);
    execute_command(0, "ip link set %s_slave_0 master %s0", devmasters[i],
                    devmasters[i]);
    execute_command(0, "ip link set %s_slave_1 master %s0", devmasters[i],
                    devmasters[i]);
    execute_command(0, "ip link set veth0_to_%s up", devmasters[i]);
    execute_command(0, "ip link set veth1_to_%s up", devmasters[i]);
  }
  execute_command(0, "ip link set bridge_slave_0 up");
  execute_command(0, "ip link set bridge_slave_1 up");

  for (i = 0; i < sizeof(devnames) / (sizeof(devnames[0])); i++) {
    char addr[32];
    snprintf_check(addr, sizeof(addr), DEV_IPV4, i + 10);
    execute_command(0, "ip -4 addr add %s/24 dev %s", addr, devnames[i]);
    snprintf_check(addr, sizeof(addr), DEV_IPV6, i + 10);
    execute_command(0, "ip -6 addr add %s/120 dev %s", addr, devnames[i]);
    snprintf_check(addr, sizeof(addr), DEV_MAC, i + 10);
    execute_command(0, "ip link set dev %s address %s", devnames[i], addr);
    execute_command(0, "ip link set dev %s up", devnames[i]);
  }
}

static void loop();

static void sandbox_common()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  setsid();

  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = 160 << 20;
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 8 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 136 << 20;
  setrlimit(RLIMIT_FSIZE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_STACK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 0;
  setrlimit(RLIMIT_CORE, &rlim);

  if (unshare(CLONE_NEWNS)) {
  }
  if (unshare(CLONE_NEWIPC)) {
  }
  if (unshare(0x02000000)) {
  }
  if (unshare(CLONE_NEWUTS)) {
  }
  if (unshare(CLONE_SYSVSEM)) {
  }
}

int wait_for_loop(int pid)
{
  if (pid < 0)
    fail("sandbox fork failed");
  int status = 0;
  while (waitpid(-1, &status, __WALL) != pid) {
  }
  return WEXITSTATUS(status);
}

static int do_sandbox_none(void)
{
  if (unshare(CLONE_NEWPID)) {
  }
  int pid = fork();
  if (pid != 0)
    return wait_for_loop(pid);

  sandbox_common();
  if (unshare(CLONE_NEWNET)) {
  }
  initialize_tun();
  initialize_netdevices();
  loop();
  doexit(1);
}

struct thread_t {
  int created, running, call;
  pthread_t th;
};

static struct thread_t threads[16];
static void execute_call(int call);
static int running;
static int collide;

static void* thr(void* arg)
{
  struct thread_t* th = (struct thread_t*)arg;
  for (;;) {
    while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
      syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
    syscall(SYS_futex, &th->running, FUTEX_WAKE);
  }
  return 0;
}

static void execute(int num_calls)
{
  int call, thread;
  running = 0;
  for (call = 0; call < num_calls; call++) {
    for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 128 << 10);
        pthread_create(&th->th, &attr, thr, th);
      }
      if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) {
        th->call = call;
        __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
        __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
        syscall(SYS_futex, &th->running, FUTEX_WAKE);
        if (collide && call % 2)
          break;
        struct timespec ts;
        ts.tv_sec = 0;
        ts.tv_nsec = 20 * 1000 * 1000;
        syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
        if (__atomic_load_n(&running, __ATOMIC_RELAXED))
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

uint64_t r[5] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
                 0x0, 0xffffffffffffffff};
void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    NONFAILING(memcpy((void*)0x20000000, "./file0", 8));
    res = syscall(__NR_creat, 0x20000000, 0xa);
    if (res != -1)
      r[0] = res;
    break;
  case 1:
    syscall(__NR_setsockopt, r[0], 6, 0x1e, 0x20000040, 0);
    break;
  case 2:
    NONFAILING(*(uint32_t*)0x20001080 = 0x1e);
    syscall(__NR_getsockopt, r[0], 0, 3, 0x20001040, 0x20001080);
    break;
  case 3:
    NONFAILING(*(uint32_t*)0x20001140 = 0x64);
    syscall(__NR_getsockopt, r[0], 0, 0, 0x200010c0, 0x20001140);
    break;
  case 4:
    syscall(__NR_ioctl, r[0], 0x540d);
    break;
  case 5:
    syscall(__NR_ioctl, r[0], 0x4b61, 0x20001180);
    break;
  case 6:
    res = syscall(__NR_socket, 0xa, 1, 0);
    if (res != -1)
      r[1] = res;
    break;
  case 7:
    NONFAILING(*(uint32_t*)0x200011c0 = 6);
    NONFAILING(*(uint16_t*)0x200011c8 = 0xa);
    NONFAILING(*(uint16_t*)0x200011ca = htobe16(0x4e24));
    NONFAILING(*(uint32_t*)0x200011cc = 2);
    NONFAILING(*(uint8_t*)0x200011d0 = 0);
    NONFAILING(*(uint8_t*)0x200011d1 = 0);
    NONFAILING(*(uint8_t*)0x200011d2 = 0);
    NONFAILING(*(uint8_t*)0x200011d3 = 0);
    NONFAILING(*(uint8_t*)0x200011d4 = 0);
    NONFAILING(*(uint8_t*)0x200011d5 = 0);
    NONFAILING(*(uint8_t*)0x200011d6 = 0);
    NONFAILING(*(uint8_t*)0x200011d7 = 0);
    NONFAILING(*(uint8_t*)0x200011d8 = 0);
    NONFAILING(*(uint8_t*)0x200011d9 = 0);
    NONFAILING(*(uint8_t*)0x200011da = 0);
    NONFAILING(*(uint8_t*)0x200011db = 0);
    NONFAILING(*(uint8_t*)0x200011dc = 0);
    NONFAILING(*(uint8_t*)0x200011dd = 0);
    NONFAILING(*(uint8_t*)0x200011de = 0);
    NONFAILING(*(uint8_t*)0x200011df = 0);
    NONFAILING(*(uint32_t*)0x200011e0 = 9);
    syscall(__NR_setsockopt, r[0], 0x29, 0x2d, 0x200011c0, 0x88);
    break;
  case 8:
    NONFAILING(memcpy((void*)0x20001280, "./file0", 8));
    NONFAILING(memcpy((void*)0x200012c0, "./file0/file0", 14));
    syscall(__NR_linkat, r[0], 0x20001280, r[0], 0x200012c0, 0x400);
    break;
  case 9:
    NONFAILING(*(uint8_t*)0x20001300 = 4);
    syscall(__NR_ioctl, r[0], 0x541c, 0x20001300);
    break;
  case 10:
    NONFAILING(*(uint64_t*)0x20001a40 = 0x20001340);
    NONFAILING(*(uint16_t*)0x20001340 = 0x18);
    NONFAILING(*(uint32_t*)0x20001342 = 1);
    NONFAILING(*(uint32_t*)0x20001346 = 0);
    NONFAILING(*(uint32_t*)0x2000134a = r[0]);
    NONFAILING(*(uint16_t*)0x2000134e = 2);
    NONFAILING(*(uint16_t*)0x20001350 = htobe16(0x4e21));
    NONFAILING(*(uint32_t*)0x20001352 = htobe32(0xe0000002));
    NONFAILING(*(uint8_t*)0x20001356 = 0);
    NONFAILING(*(uint8_t*)0x20001357 = 0);
    NONFAILING(*(uint8_t*)0x20001358 = 0);
    NONFAILING(*(uint8_t*)0x20001359 = 0);
    NONFAILING(*(uint8_t*)0x2000135a = 0);
    NONFAILING(*(uint8_t*)0x2000135b = 0);
    NONFAILING(*(uint8_t*)0x2000135c = 0);
    NONFAILING(*(uint8_t*)0x2000135d = 0);
    NONFAILING(*(uint16_t*)0x2000135e = 0);
    NONFAILING(*(uint16_t*)0x20001360 = 3);
    NONFAILING(*(uint16_t*)0x20001362 = 2);
    NONFAILING(*(uint16_t*)0x20001364 = 2);
    NONFAILING(*(uint32_t*)0x20001a48 = 0x80);
    NONFAILING(*(uint64_t*)0x20001a50 = 0x200018c0);
    NONFAILING(*(uint64_t*)0x200018c0 = 0x200013c0);
    NONFAILING(*(uint64_t*)0x200018c8 = 0);
    NONFAILING(*(uint64_t*)0x200018d0 = 0x20001400);
    NONFAILING(*(uint64_t*)0x200018d8 = 0);
    NONFAILING(*(uint64_t*)0x200018e0 = 0x20001440);
    NONFAILING(*(uint64_t*)0x200018e8 = 0);
    NONFAILING(*(uint64_t*)0x200018f0 = 0x20001480);
    NONFAILING(*(uint64_t*)0x200018f8 = 0);
    NONFAILING(*(uint64_t*)0x20001900 = 0x20001580);
    NONFAILING(*(uint64_t*)0x20001908 = 0);
    NONFAILING(*(uint64_t*)0x20001910 = 0x200015c0);
    NONFAILING(*(uint64_t*)0x20001918 = 0);
    NONFAILING(*(uint64_t*)0x20001920 = 0x20001640);
    NONFAILING(*(uint64_t*)0x20001928 = 0);
    NONFAILING(*(uint64_t*)0x20001930 = 0x20001700);
    NONFAILING(*(uint64_t*)0x20001938 = 0);
    NONFAILING(*(uint64_t*)0x20001940 = 0x20001800);
    NONFAILING(*(uint64_t*)0x20001948 = 0);
    NONFAILING(*(uint64_t*)0x20001a58 = 9);
    NONFAILING(*(uint64_t*)0x20001a60 = 0x20001980);
    NONFAILING(*(uint64_t*)0x20001980 = 0x10);
    NONFAILING(*(uint32_t*)0x20001988 = 0x19d);
    NONFAILING(*(uint32_t*)0x2000198c = 0);
    NONFAILING(*(uint64_t*)0x20001990 = 0x10);
    NONFAILING(*(uint32_t*)0x20001998 = 0x111);
    NONFAILING(*(uint32_t*)0x2000199c = 0xffffff01);
    NONFAILING(*(uint64_t*)0x20001a68 = 0x20);
    NONFAILING(*(uint32_t*)0x20001a70 = 0x20000000);
    syscall(__NR_sendmsg, r[1], 0x20001a40, 0x80);
    break;
  case 11:
    NONFAILING(*(uint32_t*)0x20001a80 = 0x20);
    syscall(__NR_ioctl, r[0], 0x5204, 0x20001a80);
    break;
  case 12:
    NONFAILING(memcpy((void*)0x20001ac0, "\x4e\x45\x54\x4d\x41\x50\x00\x00\x00"
                                         "\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                                         "\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                                         "\x00\x00",
                      29));
    NONFAILING(*(uint8_t*)0x20001add = 0);
    NONFAILING(*(uint32_t*)0x20001b00 = 0x1e);
    syscall(__NR_getsockopt, r[0], 0, 0x63, 0x20001ac0, 0x20001b00);
    break;
  case 13:
    res = syscall(__NR_socket, 2, 1, 0);
    if (res != -1)
      r[2] = res;
    break;
  case 14:
    NONFAILING(*(uint32_t*)0x20001b40 = 4);
    NONFAILING(*(uint32_t*)0x20001b44 = 0x4515);
    NONFAILING(*(uint32_t*)0x20001b48 = 0);
    NONFAILING(*(uint32_t*)0x20001b4c = -1);
    NONFAILING(*(uint8_t*)0x20001b50 = 0xf9);
    NONFAILING(*(uint8_t*)0x20001b51 = 0x64);
    NONFAILING(*(uint8_t*)0x20001b52 = 8);
    NONFAILING(*(uint8_t*)0x20001b53 = 1);
    NONFAILING(*(uint32_t*)0x20001b54 = 2);
    NONFAILING(*(uint32_t*)0x20001b58 = 3);
    NONFAILING(*(uint32_t*)0x20001b5c = 6);
    NONFAILING(*(uint32_t*)0x20001b60 = 1);
    syscall(__NR_ioctl, r[0], 0x5456, 0x20001b40);
    break;
  case 15:
    syscall(__NR_ioctl, r[2], 0x5411, 0x20001b80);
    break;
  case 16:
    NONFAILING(*(uint8_t*)0x20001bc0 = 7);
    NONFAILING(*(uint8_t*)0x20001bc1 = 0x1f);
    NONFAILING(*(uint16_t*)0x20001bc2 = 0);
    syscall(__NR_ioctl, r[0], 0x4b48, 0x20001bc0);
    break;
  case 17:
    res = syscall(__NR_gettid);
    if (res != -1)
      r[3] = res;
    break;
  case 18:
    NONFAILING(*(uint32_t*)0x20001c00 = r[3]);
    syscall(__NR_ioctl, r[0], 0x8901, 0x20001c00);
    break;
  case 19:
    NONFAILING(memcpy((void*)0x20001c40, "/dev/ptmx", 10));
    res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20001c40, 0xa0180, 0);
    if (res != -1)
      r[4] = res;
    break;
  case 20:
    NONFAILING(*(uint64_t*)0x20001f40 = 0x20001c80);
    NONFAILING(*(uint64_t*)0x20001f48 = 0xf8);
    NONFAILING(*(uint64_t*)0x20001f50 = 0x20001d80);
    NONFAILING(*(uint64_t*)0x20001f58 = 0xa0);
    NONFAILING(*(uint64_t*)0x20001f60 = 0x20001e40);
    NONFAILING(*(uint64_t*)0x20001f68 = 0x73);
    NONFAILING(*(uint64_t*)0x20001f70 = 0x20001ec0);
    NONFAILING(*(uint64_t*)0x20001f78 = 0x7f);
    syscall(__NR_readv, r[4], 0x20001f40, 4);
    break;
  }
}

void loop()
{
  execute(21);
  collide = 1;
  execute(21);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  install_segv_handler();
  do_sandbox_none();
  return 0;
}