report

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 23 at lib/refcount.c:25 refcount_warn_saturate+0x1ea/0x230 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 23 Comm: kworker/1:0 Not tainted 6.6.0-rc6-g1b70ac811a14-dirty #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events sco_sock_timeout
RIP: 0010:refcount_warn_saturate+0x1ea/0x230 lib/refcount.c:25
Code: de e8 5a fa 49 fd 84 db 0f 85 cf fe ff ff 31 ff e8 1b ff 49 fd c6 05 7a ba d4 0a 01 90 48 c7 c7 c0 da 48 8b e8 87 f5 0e fd 90 <0f> 0b 90 90 e9 aa fe ff ff 31 ff e8 f6 fe 49 fd c6 05 53 ba d4 0a
RSP: 0018:ffffc900001f7cb0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888141671e40
RDX: ffffffff81501e41 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888066def080 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff888153ddbe08
R13: ffff888066def080 R14: ffffc900001f7d80 R15: ffff88823bc3bec0
FS:  0000000000000000(0000) GS:ffff88823bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005636c7ef6aa0 CR3: 00000000695b4000 CR4: 0000000000350ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sock_hold include/net/sock.h:777 [inline]
 sco_sock_timeout+0x273/0x300 net/bluetooth/sco.c:88
 process_one_work+0x8ab/0x1730 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x931/0x1380 kernel/workqueue.c:2784
 kthread+0x2d3/0x3b0 kernel/kthread.c:388
 ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

repro.c

// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/capability.h>
#include <linux/futex.h>
#include <linux/rfkill.h>
#include <pthread.h>
#include <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#ifndef __NR_finit_module
#define __NR_finit_module 313
#endif
#ifndef __NR_landlock_create_ruleset
#define __NR_landlock_create_ruleset 444
#endif

static void sleep_ms(uint64_t ms) { usleep(ms * 1000); }

static uint64_t current_time_ms(void) {
  struct timespec ts;
  if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1);
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void thread_start(void* (*fn)(void*), void* arg) {
  pthread_t th;
  pthread_attr_t attr;
  pthread_attr_init(&attr);
  pthread_attr_setstacksize(&attr, 128 << 10);
  int i = 0;
  for (; i < 100; i++) {
    if (pthread_create(&th, &attr, fn, arg) == 0) {
      pthread_attr_destroy(&attr);
      return;
    }
    if (errno == EAGAIN) {
      usleep(50);
      continue;
    }
    break;
  }
  exit(1);
}

typedef struct {
  int state;
} event_t;

static void event_init(event_t* ev) { ev->state = 0; }

static void event_reset(event_t* ev) { ev->state = 0; }

static void event_set(event_t* ev) {
  if (ev->state) exit(1);
  __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
  syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev) {
  while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
    syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

static int event_isset(event_t* ev) {
  return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE);
}

static int event_timedwait(event_t* ev, uint64_t timeout) {
  uint64_t start = current_time_ms();
  uint64_t now = start;
  for (;;) {
    uint64_t remain = timeout - (now - start);
    struct timespec ts;
    ts.tv_sec = remain / 1000;
    ts.tv_nsec = (remain % 1000) * 1000 * 1000;
    syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts);
    if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) return 1;
    now = current_time_ms();
    if (now - start > timeout) return 0;
  }
}

static bool write_file(const char* file, const char* what, ...) {
  char buf[1024];
  va_list args;
  va_start(args, what);
  vsnprintf(buf, sizeof(buf), what, args);
  va_end(args);
  buf[sizeof(buf) - 1] = 0;
  int len = strlen(buf);
  int fd = open(file, O_WRONLY | O_CLOEXEC);
  if (fd == -1) return false;
  if (write(fd, buf, len) != len) {
    int err = errno;
    close(fd);
    errno = err;
    return false;
  }
  close(fd);
  return true;
}

const int kInitNetNsFd = 201;

#define MAX_FDS 30

static long syz_init_net_socket(volatile long domain, volatile long type,
                                volatile long proto) {
  int netns = open("/proc/self/ns/net", O_RDONLY);
  if (netns == -1) return netns;
  if (setns(kInitNetNsFd, 0)) return -1;
  int sock = syscall(__NR_socket, domain, type, proto);
  int err = errno;
  if (setns(netns, 0)) exit(1);
  close(netns);
  errno = err;
  return sock;
}

#define BTPROTO_HCI 1
#define ACL_LINK 1
#define SCAN_PAGE 2

typedef struct {
  uint8_t b[6];
} __attribute__((packed)) bdaddr_t;

#define HCI_COMMAND_PKT 1
#define HCI_EVENT_PKT 4
#define HCI_VENDOR_PKT 0xff

struct hci_command_hdr {
  uint16_t opcode;
  uint8_t plen;
} __attribute__((packed));

struct hci_event_hdr {
  uint8_t evt;
  uint8_t plen;
} __attribute__((packed));

#define HCI_EV_CONN_COMPLETE 0x03
struct hci_ev_conn_complete {
  uint8_t status;
  uint16_t handle;
  bdaddr_t bdaddr;
  uint8_t link_type;
  uint8_t encr_mode;
} __attribute__((packed));

#define HCI_EV_CONN_REQUEST 0x04
struct hci_ev_conn_request {
  bdaddr_t bdaddr;
  uint8_t dev_class[3];
  uint8_t link_type;
} __attribute__((packed));

#define HCI_EV_REMOTE_FEATURES 0x0b
struct hci_ev_remote_features {
  uint8_t status;
  uint16_t handle;
  uint8_t features[8];
} __attribute__((packed));

#define HCI_EV_CMD_COMPLETE 0x0e
struct hci_ev_cmd_complete {
  uint8_t ncmd;
  uint16_t opcode;
} __attribute__((packed));

#define HCI_OP_WRITE_SCAN_ENABLE 0x0c1a

#define HCI_OP_READ_BUFFER_SIZE 0x1005
struct hci_rp_read_buffer_size {
  uint8_t status;
  uint16_t acl_mtu;
  uint8_t sco_mtu;
  uint16_t acl_max_pkt;
  uint16_t sco_max_pkt;
} __attribute__((packed));

#define HCI_OP_READ_BD_ADDR 0x1009
struct hci_rp_read_bd_addr {
  uint8_t status;
  bdaddr_t bdaddr;
} __attribute__((packed));

#define HCI_EV_LE_META 0x3e
struct hci_ev_le_meta {
  uint8_t subevent;
} __attribute__((packed));

#define HCI_EV_LE_CONN_COMPLETE 0x01
struct hci_ev_le_conn_complete {
  uint8_t status;
  uint16_t handle;
  uint8_t role;
  uint8_t bdaddr_type;
  bdaddr_t bdaddr;
  uint16_t interval;
  uint16_t latency;
  uint16_t supervision_timeout;
  uint8_t clk_accurancy;
} __attribute__((packed));

struct hci_dev_req {
  uint16_t dev_id;
  uint32_t dev_opt;
};

struct vhci_vendor_pkt_request {
  uint8_t type;
  uint8_t opcode;
} __attribute__((packed));

struct vhci_pkt {
  uint8_t type;
  union {
    struct {
      uint8_t opcode;
      uint16_t id;
    } __attribute__((packed)) vendor_pkt;
    struct hci_command_hdr command_hdr;
  };
} __attribute__((packed));

#define HCIDEVUP _IOW('H', 201, int)
#define HCISETSCAN _IOW('H', 221, int)

static int vhci_fd = -1;

static void rfkill_unblock_all() {
  int fd = open("/dev/rfkill", O_WRONLY);
  if (fd < 0) exit(1);
  struct rfkill_event event = {0};
  event.idx = 0;
  event.type = RFKILL_TYPE_ALL;
  event.op = RFKILL_OP_CHANGE_ALL;
  event.soft = 0;
  event.hard = 0;
  if (write(fd, &event, sizeof(event)) < 0) exit(1);
  close(fd);
}

static void hci_send_event_packet(int fd, uint8_t evt, void* data,
                                  size_t data_len) {
  struct iovec iv[3];
  struct hci_event_hdr hdr;
  hdr.evt = evt;
  hdr.plen = data_len;
  uint8_t type = HCI_EVENT_PKT;
  iv[0].iov_base = &type;
  iv[0].iov_len = sizeof(type);
  iv[1].iov_base = &hdr;
  iv[1].iov_len = sizeof(hdr);
  iv[2].iov_base = data;
  iv[2].iov_len = data_len;
  if (writev(fd, iv, sizeof(iv) / sizeof(struct iovec)) < 0) exit(1);
}

static void hci_send_event_cmd_complete(int fd, uint16_t opcode, void* data,
                                        size_t data_len) {
  struct iovec iv[4];
  struct hci_event_hdr hdr;
  hdr.evt = HCI_EV_CMD_COMPLETE;
  hdr.plen = sizeof(struct hci_ev_cmd_complete) + data_len;
  struct hci_ev_cmd_complete evt_hdr;
  evt_hdr.ncmd = 1;
  evt_hdr.opcode = opcode;
  uint8_t type = HCI_EVENT_PKT;
  iv[0].iov_base = &type;
  iv[0].iov_len = sizeof(type);
  iv[1].iov_base = &hdr;
  iv[1].iov_len = sizeof(hdr);
  iv[2].iov_base = &evt_hdr;
  iv[2].iov_len = sizeof(evt_hdr);
  iv[3].iov_base = data;
  iv[3].iov_len = data_len;
  if (writev(fd, iv, sizeof(iv) / sizeof(struct iovec)) < 0) exit(1);
}

static bool process_command_pkt(int fd, char* buf, ssize_t buf_size) {
  struct hci_command_hdr* hdr = (struct hci_command_hdr*)buf;
  if (buf_size < (ssize_t)sizeof(struct hci_command_hdr) ||
      hdr->plen != buf_size - sizeof(struct hci_command_hdr))
    exit(1);
  switch (hdr->opcode) {
    case HCI_OP_WRITE_SCAN_ENABLE: {
      uint8_t status = 0;
      hci_send_event_cmd_complete(fd, hdr->opcode, &status, sizeof(status));
      return true;
    }
    case HCI_OP_READ_BD_ADDR: {
      struct hci_rp_read_bd_addr rp = {0};
      rp.status = 0;
      memset(&rp.bdaddr, 0xaa, 6);
      hci_send_event_cmd_complete(fd, hdr->opcode, &rp, sizeof(rp));
      return false;
    }
    case HCI_OP_READ_BUFFER_SIZE: {
      struct hci_rp_read_buffer_size rp = {0};
      rp.status = 0;
      rp.acl_mtu = 1021;
      rp.sco_mtu = 96;
      rp.acl_max_pkt = 4;
      rp.sco_max_pkt = 6;
      hci_send_event_cmd_complete(fd, hdr->opcode, &rp, sizeof(rp));
      return false;
    }
  }
  char dummy[0xf9] = {0};
  hci_send_event_cmd_complete(fd, hdr->opcode, dummy, sizeof(dummy));
  return false;
}

static void* event_thread(void* arg) {
  while (1) {
    char buf[1024] = {0};
    ssize_t buf_size = read(vhci_fd, buf, sizeof(buf));
    if (buf_size < 0) exit(1);
    if (buf_size > 0 && buf[0] == HCI_COMMAND_PKT) {
      if (process_command_pkt(vhci_fd, buf + 1, buf_size - 1)) break;
    }
  }
  return NULL;
}
#define HCI_HANDLE_1 200
#define HCI_HANDLE_2 201

#define HCI_PRIMARY 0
#define HCI_OP_RESET 0x0c03

static void initialize_vhci() {
  int hci_sock = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
  if (hci_sock < 0) exit(1);
  vhci_fd = open("/dev/vhci", O_RDWR);
  if (vhci_fd == -1) exit(1);
  const int kVhciFd = 202;
  if (dup2(vhci_fd, kVhciFd) < 0) exit(1);
  close(vhci_fd);
  vhci_fd = kVhciFd;
  struct vhci_vendor_pkt_request vendor_pkt_req = {HCI_VENDOR_PKT, HCI_PRIMARY};
  if (write(vhci_fd, &vendor_pkt_req, sizeof(vendor_pkt_req)) !=
      sizeof(vendor_pkt_req))
    exit(1);
  struct vhci_pkt vhci_pkt;
  if (read(vhci_fd, &vhci_pkt, sizeof(vhci_pkt)) != sizeof(vhci_pkt)) exit(1);
  if (vhci_pkt.type == HCI_COMMAND_PKT &&
      vhci_pkt.command_hdr.opcode == HCI_OP_RESET) {
    char response[1] = {0};
    hci_send_event_cmd_complete(vhci_fd, HCI_OP_RESET, response,
                                sizeof(response));
    if (read(vhci_fd, &vhci_pkt, sizeof(vhci_pkt)) != sizeof(vhci_pkt)) exit(1);
  }
  if (vhci_pkt.type != HCI_VENDOR_PKT) exit(1);
  int dev_id = vhci_pkt.vendor_pkt.id;
  pthread_t th;
  if (pthread_create(&th, NULL, event_thread, NULL)) exit(1);
  int ret = ioctl(hci_sock, HCIDEVUP, dev_id);
  if (ret) {
    if (errno == ERFKILL) {
      rfkill_unblock_all();
      ret = ioctl(hci_sock, HCIDEVUP, dev_id);
    }
    if (ret && errno != EALREADY) exit(1);
  }
  struct hci_dev_req dr = {0};
  dr.dev_id = dev_id;
  dr.dev_opt = SCAN_PAGE;
  if (ioctl(hci_sock, HCISETSCAN, &dr)) exit(1);
  struct hci_ev_conn_request request;
  memset(&request, 0, sizeof(request));
  memset(&request.bdaddr, 0xaa, 6);
  *(uint8_t*)&request.bdaddr.b[5] = 0x10;
  request.link_type = ACL_LINK;
  hci_send_event_packet(vhci_fd, HCI_EV_CONN_REQUEST, &request,
                        sizeof(request));
  struct hci_ev_conn_complete complete;
  memset(&complete, 0, sizeof(complete));
  complete.status = 0;
  complete.handle = HCI_HANDLE_1;
  memset(&complete.bdaddr, 0xaa, 6);
  *(uint8_t*)&complete.bdaddr.b[5] = 0x10;
  complete.link_type = ACL_LINK;
  complete.encr_mode = 0;
  hci_send_event_packet(vhci_fd, HCI_EV_CONN_COMPLETE, &complete,
                        sizeof(complete));
  struct hci_ev_remote_features features;
  memset(&features, 0, sizeof(features));
  features.status = 0;
  features.handle = HCI_HANDLE_1;
  hci_send_event_packet(vhci_fd, HCI_EV_REMOTE_FEATURES, &features,
                        sizeof(features));
  struct {
    struct hci_ev_le_meta le_meta;
    struct hci_ev_le_conn_complete le_conn;
  } le_conn;
  memset(&le_conn, 0, sizeof(le_conn));
  le_conn.le_meta.subevent = HCI_EV_LE_CONN_COMPLETE;
  memset(&le_conn.le_conn.bdaddr, 0xaa, 6);
  *(uint8_t*)&le_conn.le_conn.bdaddr.b[5] = 0x11;
  le_conn.le_conn.role = 1;
  le_conn.le_conn.handle = HCI_HANDLE_2;
  hci_send_event_packet(vhci_fd, HCI_EV_LE_META, &le_conn, sizeof(le_conn));
  pthread_join(th, NULL);
  close(hci_sock);
}

static void setup_common() {
  if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
  }
}

static void setup_binderfs() {
  if (mkdir("/dev/binderfs", 0777)) {
  }
  if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
  }
  if (symlink("/dev/binderfs", "./binderfs")) {
  }
}

static void loop();

static void sandbox_common() {
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setsid();
  int netns = open("/proc/self/ns/net", O_RDONLY);
  if (netns == -1) exit(1);
  if (dup2(netns, kInitNetNsFd) < 0) exit(1);
  close(netns);
  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = (200 << 20);
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 32 << 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 = 128 << 20;
  setrlimit(RLIMIT_CORE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 256;
  setrlimit(RLIMIT_NOFILE, &rlim);
  if (unshare(CLONE_NEWNS)) {
  }
  if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
  }
  if (unshare(CLONE_NEWIPC)) {
  }
  if (unshare(0x02000000)) {
  }
  if (unshare(CLONE_NEWUTS)) {
  }
  if (unshare(CLONE_SYSVSEM)) {
  }
  typedef struct {
    const char* name;
    const char* value;
  } sysctl_t;
  static const sysctl_t sysctls[] = {
      {"/proc/sys/kernel/shmmax", "16777216"},
      {"/proc/sys/kernel/shmall", "536870912"},
      {"/proc/sys/kernel/shmmni", "1024"},
      {"/proc/sys/kernel/msgmax", "8192"},
      {"/proc/sys/kernel/msgmni", "1024"},
      {"/proc/sys/kernel/msgmnb", "1024"},
      {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
  };
  unsigned i;
  for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
    write_file(sysctls[i].name, sysctls[i].value);
}

static int wait_for_loop(int pid) {
  if (pid < 0) exit(1);
  int status = 0;
  while (waitpid(-1, &status, __WALL) != pid) {
  }
  return WEXITSTATUS(status);
}

static void drop_caps(void) {
  struct __user_cap_header_struct cap_hdr = {};
  struct __user_cap_data_struct cap_data[2] = {};
  cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
  cap_hdr.pid = getpid();
  if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1);
  const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
  cap_data[0].effective &= ~drop;
  cap_data[0].permitted &= ~drop;
  cap_data[0].inheritable &= ~drop;
  if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1);
}

static int do_sandbox_none(void) {
  if (unshare(CLONE_NEWPID)) {
  }
  int pid = fork();
  if (pid != 0) return wait_for_loop(pid);
  setup_common();
  initialize_vhci();
  sandbox_common();
  drop_caps();
  if (unshare(CLONE_NEWNET)) {
  }
  write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
  setup_binderfs();
  loop();
  exit(1);
}

static void kill_and_wait(int pid, int* status) {
  kill(-pid, SIGKILL);
  kill(pid, SIGKILL);
  for (int i = 0; i < 100; i++) {
    if (waitpid(-1, status, WNOHANG | __WALL) == pid) return;
    usleep(1000);
  }
  DIR* dir = opendir("/sys/fs/fuse/connections");
  if (dir) {
    for (;;) {
      struct dirent* ent = readdir(dir);
      if (!ent) break;
      if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
        continue;
      char abort[300];
      snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
               ent->d_name);
      int fd = open(abort, O_WRONLY);
      if (fd == -1) {
        continue;
      }
      if (write(fd, abort, 1) < 0) {
      }
      close(fd);
    }
    closedir(dir);
  } else {
  }
  while (waitpid(-1, status, __WALL) != pid) {
  }
}

static void setup_test() {
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  write_file("/proc/self/oom_score_adj", "1000");
}

static void close_fds() {
  for (int fd = 3; fd < MAX_FDS; fd++) close(fd);
}

struct thread_t {
  int created, call;
  event_t ready, done;
};

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

static void* thr(void* arg) {
  struct thread_t* th = (struct thread_t*)arg;
  for (;;) {
    event_wait(&th->ready);
    event_reset(&th->ready);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    event_set(&th->done);
  }
  return 0;
}

static void execute_one(void) {
  int i, call, thread;
  for (call = 0; call < 15; call++) {
    for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0]));
         thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        event_init(&th->ready);
        event_init(&th->done);
        event_set(&th->done);
        thread_start(thr, th);
      }
      if (!event_isset(&th->done)) continue;
      event_reset(&th->done);
      th->call = call;
      __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
      event_set(&th->ready);
      if (call == 1 || call == 4 || call == 5) break;
      event_timedwait(&th->done, 50);
      break;
    }
  }
  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
    sleep_ms(1);
  close_fds();
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void) {
  int iter = 0;
  for (;; iter++) {
    int pid = fork();
    if (pid < 0) exit(1);
    if (pid == 0) {
      setup_test();
      execute_one();
      exit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break;
      sleep_ms(1);
      if (current_time_ms() - start < 5000) continue;
      kill_and_wait(pid, &status);
      break;
    }
  }
}

uint64_t r[1] = {0xffffffffffffffff};

void execute_call(int call) {
  intptr_t res = 0;
  switch (call) {
    case 0:
      res = -1;
      res = syz_init_net_socket(/*fam=*/0x1f, /*type=*/5, /*proto=*/2);
      if (res != -1) r[0] = res;
      break;
    case 1:
      *(uint16_t*)0x200002c0 = 0x1f;
      memset((void*)0x200002c2, 0, 6);
      syscall(__NR_connect, /*fd=*/r[0], /*addr=*/0x200002c0ul,
              /*addrlen=*/8ul);
      break;
    case 2:
      *(uint16_t*)0x20000500 = 0x1f;
      memset((void*)0x20000502, 170, 5);
      *(uint8_t*)0x20000507 = 0x11;
      syscall(__NR_connect, /*fd=*/r[0], /*addr=*/0x20000500ul,
              /*addrlen=*/8ul);
      break;
    case 3:
      syscall(__NR_shutdown, /*fd=*/-1, /*how=*/0ul);
      break;
    case 4:
      syscall(__NR_open, /*file=*/0ul, /*flags=*/0x6143c2ul, /*mode=*/0x19ul);
      break;
    case 5:
      syscall(__NR_mkdirat, /*fd=*/-1, /*path=*/0ul, /*mode=*/8ul);
      {
        int i;
        for (i = 0; i < 32; i++) {
          syscall(__NR_mkdirat, /*fd=*/-1, /*path=*/0ul, /*mode=*/8ul);
        }
      }
      break;
    case 6:
      *(uint64_t*)0x20000400 = 0x2081;
      *(uint64_t*)0x20000408 = 1;
      syscall(__NR_landlock_create_ruleset, /*attr=*/0x20000400ul,
              /*size=*/0x10ul, /*flags=*/0ul);
      break;
    case 7:
      syscall(__NR_ioctl, /*fd=*/-1, /*cmd=*/0x708, /*arg=*/0ul);
      break;
    case 8:
      syscall(__NR_getsockopt, /*fd=*/-1, /*level=*/1, /*optname=*/0x11,
              /*optval=*/0ul, /*optlen=*/0ul);
      break;
    case 9:
      syscall(__NR_getsockopt, /*fd=*/-1, /*level=*/0x10f, /*opt=*/0x84,
              /*val=*/0ul, /*len=*/0ul);
      break;
    case 10:
      syscall(__NR_accept, /*fd=*/-1, /*peer=*/0ul, /*peerlen=*/0ul);
      break;
    case 11:
      syscall(__NR_write, /*fd=*/-1, /*buf=*/0x20000a00ul, /*count=*/0ul);
      break;
    case 12:
      syscall(__NR_sendfile, /*fdout=*/-1, /*fdin=*/-1, /*off=*/0ul,
              /*count=*/0xef82ul);
      break;
    case 13:
      *(uint16_t*)0x20000080 = 0x1f;
      memset((void*)0x20000082, 255, 6);
      syscall(__NR_connect, /*fd=*/-1, /*addr=*/0x20000080ul, /*addrlen=*/8ul);
      break;
    case 14:
      syscall(__NR_finit_module, /*fd=*/-1, /*args=*/0ul, /*flags=*/1ul);
      break;
  }
}
int main(void) {
  syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul,
          /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
  do_sandbox_none();
  return 0;
}

repro.txt

r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2)
connect$bt_sco(r0, &(0x7f00000002c0), 0x8) (async)
connect$bt_sco(r0, &(0x7f0000000500)={0x1f, @fixed={'\xaa\xaa\xaa\xaa\xaa', 0x11}}, 0x8)
shutdown(0xffffffffffffffff, 0x0)
open(0x0, 0x6143c2, 0x19) (async)
mkdirat(0xffffffffffffffff, 0x0, 0x8) (async, rerun: 32)
landlock_create_ruleset(&(0x7f0000000400)={0x2081, 0x1}, 0x10, 0x0)
ioctl$I2C_RDWR(0xffffffffffffffff, 0x708, 0x0)
getsockopt$sock_cred(0xffffffffffffffff, 0x1, 0x11, 0x0, 0x0)
getsockopt$TIPC_SOCK_RECVQ_DEPTH(0xffffffffffffffff, 0x10f, 0x84, 0x0, 0x0)
accept$alg(0xffffffffffffffff, 0x0, 0x0)
write(0xffffffffffffffff, &(0x7f0000000a00), 0x0)
sendfile(0xffffffffffffffff, 0xffffffffffffffff, 0x0, 0xef82)
connect$bt_sco(0xffffffffffffffff, &(0x7f0000000080)={0x1f, @none}, 0x8)
finit_module(0xffffffffffffffff, 0x0, 0x1)