syzkaller-repros/linux/7c7bd742d3b6b7473427759ad255c581dbd94412.c

// BUG: using __this_cpu_add() in preemptible code in check_preemption_disabled
// https://syzkaller.appspot.com/bug?id=7c7bd742d3b6b7473427759ad255c581dbd94412
// status:open
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <linux/futex.h>
#include <linux/net.h>
#include <netinet/in.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.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 <stdlib.h>
#include <string.h>
#include <sys/stat.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 exitf(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(kRetryStatus);
}

#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)

#define BITMASK_LEN_OFF(type, bf_off, bf_len)                                  \
  (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))

#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)                      \
  if ((bf_off) == 0 && (bf_len) == 0) {                                        \
    *(type*)(addr) = (type)(val);                                              \
  } else {                                                                     \
    type new_val = *(type*)(addr);                                             \
    new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));                     \
    new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off);          \
    *(type*)(addr) = new_val;                                                  \
  }

struct csum_inet {
  uint32_t acc;
};

static void csum_inet_init(struct csum_inet* csum)
{
  csum->acc = 0;
}

static void csum_inet_update(struct csum_inet* csum, const uint8_t* data,
                             size_t length)
{
  if (length == 0)
    return;

  size_t i;
  for (i = 0; i < length - 1; i += 2)
    csum->acc += *(uint16_t*)&data[i];

  if (length & 1)
    csum->acc += (uint16_t)data[length - 1];

  while (csum->acc > 0xffff)
    csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16);
}

static uint16_t csum_inet_digest(struct csum_inet* csum)
{
  return ~csum->acc;
}

static uint64_t current_time_ms()
{
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    fail("clock_gettime failed");
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void use_temporary_dir()
{
  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    fail("failed to mkdtemp");
  if (chmod(tmpdir, 0777))
    fail("failed to chmod");
  if (chdir(tmpdir))
    fail("failed to chdir");
}

struct ipt_getinfo {
  char name[32];
  unsigned int valid_hooks;
  unsigned int hook_entry[5];
  unsigned int underflow[5];
  unsigned int num_entries;
  unsigned int size;
};

struct ipt_get_entries {
  char name[32];
  unsigned int size;
  void* entrytable[1024 / sizeof(void*)];
};

struct xt_counters {
  uint64_t pcnt, bcnt;
};

struct ipt_replace {
  char name[32];
  unsigned int valid_hooks;
  unsigned int num_entries;
  unsigned int size;
  unsigned int hook_entry[5];
  unsigned int underflow[5];
  unsigned int num_counters;
  struct xt_counters* counters;
  char entrytable[1024];
};

struct ipt_table_desc {
  const char* name;
  struct ipt_getinfo info;
  struct ipt_get_entries entries;
  struct ipt_replace replace;
  struct xt_counters counters[10];
};

static struct ipt_table_desc ipv4_tables[] = {
    {.name = "filter"}, {.name = "nat"},      {.name = "mangle"},
    {.name = "raw"},    {.name = "security"},
};

#define IPT_BASE_CTL 64
#define IPT_SO_SET_REPLACE (IPT_BASE_CTL)
#define IPT_SO_GET_INFO (IPT_BASE_CTL)
#define IPT_SO_GET_ENTRIES (IPT_BASE_CTL + 1)

static void checkpoint_net_namespace(void)
{
  socklen_t optlen;
  unsigned i;
  int fd;

  fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (fd == -1)
    fail("socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)");
  for (i = 0; i < sizeof(ipv4_tables) / sizeof(ipv4_tables[0]); i++) {
    struct ipt_table_desc* table = &ipv4_tables[i];
    strcpy(table->info.name, table->name);
    strcpy(table->entries.name, table->name);
    strcpy(table->replace.name, table->name);
    optlen = sizeof(table->info);
    if (getsockopt(fd, SOL_IP, IPT_SO_GET_INFO, &table->info, &optlen)) {
      switch (errno) {
      case EPERM:
      case ENOENT:
      case ENOPROTOOPT:
        continue;
      }
      fail("getsockopt(IPT_SO_GET_INFO)");
    }
    if (table->info.size > sizeof(table->entries.entrytable))
      fail("table size is too large: %u", table->info.size);
    if (table->info.num_entries >
        sizeof(table->counters) / sizeof(table->counters[0]))
      fail("too many counters: %u", table->info.num_entries);
    table->entries.size = table->info.size;
    optlen = sizeof(table->entries) - sizeof(table->entries.entrytable) +
             table->info.size;
    if (getsockopt(fd, SOL_IP, IPT_SO_GET_ENTRIES, &table->entries, &optlen))
      fail("getsockopt(IPT_SO_GET_ENTRIES)");
    table->replace.valid_hooks = table->info.valid_hooks;
    table->replace.num_entries = table->info.num_entries;
    table->replace.counters = table->counters;
    table->replace.size = table->info.size;
    memcpy(table->replace.hook_entry, table->info.hook_entry,
           sizeof(table->replace.hook_entry));
    memcpy(table->replace.underflow, table->info.underflow,
           sizeof(table->replace.underflow));
    memcpy(table->replace.entrytable, table->entries.entrytable,
           table->info.size);
  }
  close(fd);
}

static void reset_net_namespace(void)
{
  struct ipt_get_entries entries;
  struct ipt_getinfo info;
  socklen_t optlen;
  unsigned i;
  int fd;

  memset(&info, 0, sizeof(info));
  memset(&entries, 0, sizeof(entries));
  fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (fd == -1)
    fail("socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)");
  for (i = 0; i < sizeof(ipv4_tables) / sizeof(ipv4_tables[0]); i++) {
    struct ipt_table_desc* table = &ipv4_tables[i];
    if (table->info.valid_hooks == 0)
      continue;
    strcpy(info.name, table->name);
    optlen = sizeof(info);
    if (getsockopt(fd, SOL_IP, IPT_SO_GET_INFO, &info, &optlen))
      fail("getsockopt(IPT_SO_GET_INFO)");
    if (memcmp(&table->info, &info, sizeof(table->info)) == 0) {
      strcpy(entries.name, table->name);
      entries.size = table->info.size;
      optlen = sizeof(entries) - sizeof(entries.entrytable) + entries.size;
      if (getsockopt(fd, SOL_IP, IPT_SO_GET_ENTRIES, &entries, &optlen))
        fail("getsockopt(IPT_SO_GET_ENTRIES)");
      if (memcmp(&table->entries, &entries, optlen) == 0)
        continue;
    }
    table->replace.num_counters = info.num_entries;
    optlen = sizeof(table->replace) - sizeof(table->replace.entrytable) +
             table->replace.size;
    if (setsockopt(fd, SOL_IP, IPT_SO_SET_REPLACE, &table->replace, optlen))
      fail("setsockopt(IPT_SO_SET_REPLACE)");
  }
  close(fd);
}

static void remove_dir(const char* dir)
{
  DIR* dp;
  struct dirent* ep;
  int iter = 0;
retry:
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exitf("opendir(%s) failed due to NOFILE, exiting", dir);
    }
    exitf("opendir(%s) failed", dir);
  }
  while ((ep = readdir(dp))) {
    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
      continue;
    char filename[FILENAME_MAX];
    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
    struct stat st;
    if (lstat(filename, &st))
      exitf("lstat(%s) failed", filename);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      if (unlink(filename) == 0)
        break;
      if (errno == EROFS) {
        break;
      }
      if (errno != EBUSY || i > 100)
        exitf("unlink(%s) failed", filename);
      if (umount2(filename, MNT_DETACH))
        exitf("umount(%s) failed", filename);
    }
  }
  closedir(dp);
  int i;
  for (i = 0;; i++) {
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EROFS) {
        break;
      }
      if (errno == EBUSY) {
        if (umount2(dir, MNT_DETACH))
          exitf("umount(%s) failed", dir);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exitf("rmdir(%s) failed", dir);
  }
}

static void test();

void loop()
{
  int iter;
  checkpoint_net_namespace();
  for (iter = 0;; iter++) {
    char cwdbuf[256];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      fail("failed to mkdir");
    int pid = fork();
    if (pid < 0)
      fail("loop fork failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      if (chdir(cwdbuf))
        fail("failed to chdir");
      test();
      doexit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      int res = waitpid(-1, &status, __WALL | WNOHANG);
      if (res == pid)
        break;
      usleep(1000);
      if (current_time_ms() - start > 5 * 1000) {
        kill(-pid, SIGKILL);
        kill(pid, SIGKILL);
        while (waitpid(-1, &status, __WALL) != pid) {
        }
        break;
      }
    }
    remove_dir(cwdbuf);
    reset_net_namespace();
  }
}

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 (running)
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

long r[1];
uint64_t procid;
void execute_call(int call)
{
  switch (call) {
  case 0:
    syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0);
    break;
  case 1:
    r[0] = syscall(__NR_socket, 2, 1, 0);
    break;
  case 2:
    *(uint32_t*)0x2039c000 = 1;
    syscall(__NR_setsockopt, r[0], 6, 0x10000000013, 0x2039c000, 4);
    break;
  case 3:
    *(uint32_t*)0x20383000 = 1;
    syscall(__NR_setsockopt, r[0], 6, 0x14, 0x20383000, 4);
    break;
  case 4:
    *(uint16_t*)0x20e45ff0 = 2;
    *(uint16_t*)0x20e45ff2 = 0;
    *(uint32_t*)0x20e45ff4 = htobe32(0x7f000001);
    *(uint8_t*)0x20e45ff8 = 0;
    *(uint8_t*)0x20e45ff9 = 0;
    *(uint8_t*)0x20e45ffa = 0;
    *(uint8_t*)0x20e45ffb = 0;
    *(uint8_t*)0x20e45ffc = 0;
    *(uint8_t*)0x20e45ffd = 0;
    *(uint8_t*)0x20e45ffe = 0;
    *(uint8_t*)0x20e45fff = 0;
    syscall(__NR_sendto, r[0], 0x20482000, 0xffffffffffffff56,
            0x800000120000401, 0x20e45ff0, 0x10);
    break;
  case 5:
    *(uint64_t*)0x20fd6000 = 0x20611ff4;
    *(uint32_t*)0x20fd6008 = 0xc;
    *(uint64_t*)0x20fd6010 = 0x20f75000;
    *(uint64_t*)0x20fd6018 = 1;
    *(uint64_t*)0x20fd6020 = 0;
    *(uint64_t*)0x20fd6028 = 0;
    *(uint32_t*)0x20fd6030 = 0;
    *(uint16_t*)0x20611ff4 = 0x10;
    *(uint16_t*)0x20611ff6 = 0;
    *(uint32_t*)0x20611ff8 = 0;
    *(uint32_t*)0x20611ffc = 0;
    *(uint64_t*)0x20f75000 = 0x20a38000;
    *(uint64_t*)0x20f75008 = 0x14;
    *(uint32_t*)0x20a38000 = 0x14;
    *(uint16_t*)0x20a38004 = 0;
    *(uint16_t*)0x20a38006 = 0;
    *(uint32_t*)0x20a38008 = 0;
    *(uint32_t*)0x20a3800c = 0;
    *(uint8_t*)0x20a38010 = 0;
    *(uint8_t*)0x20a38011 = 0;
    *(uint16_t*)0x20a38012 = 0;
    syscall(__NR_sendmsg, r[0], 0x20fd6000, 0);
    break;
  case 6:
    *(uint32_t*)0x20f53ffc = 0x1c;
    syscall(__NR_getsockname, -1, 0x2062c000, 0x20f53ffc);
    break;
  case 7:
    memcpy((void*)0x200fafef, "/selinux/relabel", 17);
    syscall(__NR_openat, 0xffffffffffffff9c, 0x200fafef, 2, 0);
    break;
  case 8:
    *(uint8_t*)0x2018f000 = -1;
    *(uint8_t*)0x2018f001 = -1;
    *(uint8_t*)0x2018f002 = -1;
    *(uint8_t*)0x2018f003 = -1;
    *(uint8_t*)0x2018f004 = -1;
    *(uint8_t*)0x2018f005 = -1;
    *(uint8_t*)0x2018f006 = 0;
    *(uint8_t*)0x2018f007 = 0;
    *(uint8_t*)0x2018f008 = 0x14;
    *(uint8_t*)0x2018f009 = 0;
    *(uint8_t*)0x2018f00a = 0;
    *(uint8_t*)0x2018f00b = 0;
    *(uint16_t*)0x2018f00c = htobe16(0x800);
    STORE_BY_BITMASK(uint8_t, 0x2018f00e, 5, 0, 4);
    STORE_BY_BITMASK(uint8_t, 0x2018f00e, 4, 4, 4);
    STORE_BY_BITMASK(uint8_t, 0x2018f00f, 0, 0, 2);
    STORE_BY_BITMASK(uint8_t, 0x2018f00f, 0, 2, 6);
    *(uint16_t*)0x2018f010 = htobe16(0x24);
    *(uint16_t*)0x2018f012 = 0;
    *(uint16_t*)0x2018f014 = htobe16(0);
    *(uint8_t*)0x2018f016 = 0;
    *(uint8_t*)0x2018f017 = 0x11;
    *(uint16_t*)0x2018f018 = 0;
    *(uint8_t*)0x2018f01a = 0xac;
    *(uint8_t*)0x2018f01b = 0x14;
    *(uint8_t*)0x2018f01c = 0;
    *(uint8_t*)0x2018f01d = 0xbb;
    *(uint32_t*)0x2018f01e = htobe32(0xe0000001);
    *(uint16_t*)0x2018f022 = 0;
    *(uint16_t*)0x2018f024 = htobe16(0x4e21 + procid * 4);
    *(uint8_t*)0x2018f026 = 4;
    STORE_BY_BITMASK(uint8_t, 0x2018f027, 1, 0, 4);
    STORE_BY_BITMASK(uint8_t, 0x2018f027, 0, 4, 4);
    *(uint16_t*)0x2018f028 = 0;
    STORE_BY_BITMASK(uint8_t, 0x2018f02a, 0, 0, 1);
    STORE_BY_BITMASK(uint8_t, 0x2018f02a, 0, 1, 4);
    STORE_BY_BITMASK(uint8_t, 0x2018f02a, 0, 5, 3);
    memcpy((void*)0x2018f02b, "\xd7\x3c\xde", 3);
    *(uint8_t*)0x2018f02e = 0;
    memcpy((void*)0x2018f02f, "\xf5\x34\x75", 3);
    struct csum_inet csum_1;
    csum_inet_init(&csum_1);
    csum_inet_update(&csum_1, (const uint8_t*)0x2018f01a, 4);
    csum_inet_update(&csum_1, (const uint8_t*)0x2018f01e, 4);
    uint16_t csum_1_chunk_2 = 0x2100;
    csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_2, 2);
    uint16_t csum_1_chunk_3 = 0x1000;
    csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_3, 2);
    csum_inet_update(&csum_1, (const uint8_t*)0x2018f022, 16);
    *(uint16_t*)0x2018f028 = csum_inet_digest(&csum_1);
    struct csum_inet csum_2;
    csum_inet_init(&csum_2);
    csum_inet_update(&csum_2, (const uint8_t*)0x2018f00e, 20);
    *(uint16_t*)0x2018f018 = csum_inet_digest(&csum_2);
    break;
  }
}

void test()
{
  memset(r, -1, sizeof(r));
  execute(9);
  collide = 1;
  execute(9);
}

int main()
{
  char* cwd = get_current_dir_name();
  for (procid = 0; procid < 8; procid++) {
    if (fork() == 0) {
      for (;;) {
        if (chdir(cwd))
          fail("failed to chdir");
        use_temporary_dir();
        loop();
      }
    }
  }
  sleep(1000000);
  return 0;
}