text: // possible deadlock in start_sync_thread
  // https://syzkaller.appspot.com/bug?id=b6245f586d47a590eea7255ddd880a0b477951bc
  // status:open
  // 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/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 <sched.h>
  #include <signal.h>
  #include <stdarg.h>
  #include <stdarg.h>
  #include <stdbool.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <stdio.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 <stdarg.h>
  #include <stdint.h>
  #include <stdio.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 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);
    }
  }
  
  #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)) {
    }
  }
  
  static int do_sandbox_none(void)
  {
    if (unshare(CLONE_NEWPID)) {
    }
    int pid = fork();
    if (pid < 0)
      fail("sandbox fork failed");
    if (pid)
      return pid;
  
    sandbox_common();
    if (unshare(CLONE_NEWNET)) {
    }
    initialize_netdevices();
    loop();
    doexit(1);
  }
  
  uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};
  void loop()
  {
    long res = 0;
    res = syscall(__NR_socket, 2, 3, 2);
    if (res != -1)
      r[0] = res;
    *(uint32_t*)0x20000080 = 0;
    syscall(__NR_setsockopt, r[0], 0, 0xc8, 0x20000080, 4);
    *(uint32_t*)0x200000c0 = 0;
    syscall(__NR_setsockopt, r[0], 0, 5, 0x200000c0, 4);
    res = syscall(__NR_socket, 0xa, 1, 0);
    if (res != -1)
      r[1] = res;
    *(uint32_t*)0x20000000 = 1;
    memcpy((void*)0x20000004, "veth0_to_bridge", 16);
    *(uint32_t*)0x20000014 = 3;
    syscall(__NR_setsockopt, r[1], 0, 0x48b, 0x20000000, 0x18);
  }
  
  int main()
  {
    syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
    int pid = do_sandbox_none();
    int status = 0;
    while (waitpid(pid, &status, __WALL) != pid) {
    }
    return 0;
  }
  