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Message-ID: <31142ccf9bd1893b773f53ff51025a27a8179367.camel@elektrobit.com>
Date: Wed, 13 Mar 2024 12:15:24 +0000
From: Weiß, Simone <Simone.Weiss@...ktrobit.com>
To: "tj@...nel.org" <tj@...nel.org>
CC: "jiangshanlai@...il.com" <jiangshanlai@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: BUG: MAX_LOCKDEP_ENTRIES too low! triggered by ext4&workqueue

Dear all,

For some experimentation, I have been running fuzzing campaigns and I
noticed  BUG: MAX_LOCKDEP_ENTRIES too low! most likely triggered by ext4
operations.

As I found a C reproducer in my setup, it could be bisected being introduced
with the following:
commit 967b494e2fd143a9c1a3201422aceadb5fa9fbfc
Author: Tejun Heo <tj@...nel.org>
Date:   Mon Aug 7 15:57:23 2023 -1000

    workqueue: Use a kthread_worker to release pool_workqueues
    
    pool_workqueue release path is currently bounced to system_wq; however, this
    is a bit tricky because this bouncing occurs while holding a pool lock and
    thus has risk of causing a A-A deadlock. This is currently addressed by the
    fact that only unbound workqueues use this bouncing path and system_wq is a
    per-cpu workqueue.
 
...

It was reproducible on v6.6.16 and v6.16.21.
The C reproducer is automatically generated by syzkaller and included below.

If you need any further information, just let me know.

Best,
Simone

Sample Crash
------------
BUG: MAX_LOCKDEP_ENTRIES too low!
turning off the locking correctness validator.
CPU: 0 PID: 1011 Comm: syz-executor232 Not tainted 6.6.16-eb-corbos-standard-
syzkaller-geb3e299184cc #0
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x128/0x214 arch/arm64/kernel/stacktrace.c:233
 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xac/0x128 lib/dump_stack.c:106
 dump_stack+0x20/0x2c lib/dump_stack.c:113
 alloc_list_entry kernel/locking/lockdep.c:1397 [inline]
 add_lock_to_list+0x24c/0x2d8 kernel/locking/lockdep.c:1418
 check_prev_add kernel/locking/lockdep.c:3204 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x35dc/0x6344 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x47c/0x770 kernel/locking/lockdep.c:5719
 _raw_spin_lock_nested+0x50/0x6c kernel/locking/spinlock.c:378
 raw_spin_rq_lock_nested kernel/sched/core.c:558 [inline]
 raw_spin_rq_lock kernel/sched/sched.h:1372 [inline]
 rq_lock kernel/sched/sched.h:1681 [inline]
 __schedule+0x218/0x2448 kernel/sched/core.c:6614
 preempt_schedule_irq+0x80/0x1ac kernel/sched/core.c:7008
 arm64_preempt_schedule_irq+0x3c/0x54 arch/arm64/kernel/entry-common.c:267
 __el1_irq arch/arm64/kernel/entry-common.c:505 [inline]
 el1_interrupt+0x3c/0x54 arch/arm64/kernel/entry-common.c:517
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:522
 el1h_64_irq+0x68/0x6c arch/arm64/kernel/entry.S:595
 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:182 [inline]
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:202 [inline]
 lock_acquire kernel/locking/lockdep.c:5757 [inline]
 lock_acquire+0x4c4/0x770 kernel/locking/lockdep.c:5719
 __flush_workqueue+0x124/0xf28 kernel/workqueue.c:3140
 drain_workqueue+0x184/0x36c kernel/workqueue.c:3305
 destroy_workqueue+0xb4/0x9a0 kernel/workqueue.c:4800
 ext4_put_super+0xe0/0x924 fs/ext4/super.c:1311
 generic_shutdown_super+0x120/0x324 fs/super.c:693
 kill_block_super+0x3c/0x74 fs/super.c:1646
 ext4_kill_sb+0x60/0xb8 fs/ext4/super.c:7320
 deactivate_locked_super+0xa0/0x1a8 fs/super.c:481
 deactivate_super fs/super.c:514 [inline]
 deactivate_super+0x118/0x148 fs/super.c:510
 cleanup_mnt+0x1b8/0x338 fs/namespace.c:1254
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1261
 task_work_run+0x148/0x254 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0xe04/0x18f4 arch/arm64/kernel/signal.c:1305
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:144 [inline]
 el0_svc+0x11c/0x140 arch/arm64/kernel/entry-common.c:679
 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:696
 el0t_64_sync+0x194/0x198 arch/arm64/kernel/entry.S:599

Reproducer
----------
// https://None.appspot.com/bug?id=422a59d59663a31fd6b1d700eab33c89c33a029b
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <linux/capability.h>
#include <linux/loop.h>

#ifndef __NR_memfd_create
#define __NR_memfd_create 279
#endif
#ifndef __NR_mmap
#define __NR_mmap 222
#endif

static unsigned long long procid;

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 use_temporary_dir(void)
{
  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    exit(1);
  if (chmod(tmpdir, 0777))
    exit(1);
  if (chdir(tmpdir))
    exit(1);
}

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;
}

#define MAX_FDS 30

//% This code is derived from puff.{c,h}, found in the zlib development. The
//% original files come with the following copyright notice:

//% Copyright (C) 2002-2013 Mark Adler, all rights reserved
//% version 2.3, 21 Jan 2013
//% This software is provided 'as-is', without any express or implied
//% warranty.  In no event will the author be held liable for any damages
//% arising from the use of this software.
//% Permission is granted to anyone to use this software for any purpose,
//% including commercial applications, and to alter it and redistribute it
//% freely, subject to the following restrictions:
//% 1. The origin of this software must not be misrepresented; you must not
//%    claim that you wrote the original software. If you use this software
//%    in a product, an acknowledgment in the product documentation would be
//%    appreciated but is not required.
//% 2. Altered source versions must be plainly marked as such, and must not be
//%    misrepresented as being the original software.
//% 3. This notice may not be removed or altered from any source distribution.
//% Mark Adler    madler@...mni.caltech.edu

//% BEGIN CODE DERIVED FROM puff.{c,h}

#define MAXBITS 15
#define MAXLCODES 286
#define MAXDCODES 30
#define MAXCODES (MAXLCODES + MAXDCODES)
#define FIXLCODES 288

struct puff_state {
  unsigned char* out;
  unsigned long outlen;
  unsigned long outcnt;
  const unsigned char* in;
  unsigned long inlen;
  unsigned long incnt;
  int bitbuf;
  int bitcnt;
  jmp_buf env;
};
static int puff_bits(struct puff_state* s, int need)
{
  long val = s->bitbuf;
  while (s->bitcnt < need) {
    if (s->incnt == s->inlen)
      longjmp(s->env, 1);
    val |= (long)(s->in[s->incnt++]) << s->bitcnt;
    s->bitcnt += 8;
  }
  s->bitbuf = (int)(val >> need);
  s->bitcnt -= need;
  return (int)(val & ((1L << need) - 1));
}
static int puff_stored(struct puff_state* s)
{
  s->bitbuf = 0;
  s->bitcnt = 0;
  if (s->incnt + 4 > s->inlen)
    return 2;
  unsigned len = s->in[s->incnt++];
  len |= s->in[s->incnt++] << 8;
  if (s->in[s->incnt++] != (~len & 0xff) ||
      s->in[s->incnt++] != ((~len >> 8) & 0xff))
    return -2;
  if (s->incnt + len > s->inlen)
    return 2;
  if (s->outcnt + len > s->outlen)
    return 1;
  for (; len--; s->outcnt++, s->incnt++) {
    if (s->in[s->incnt])
      s->out[s->outcnt] = s->in[s->incnt];
  }
  return 0;
}
struct puff_huffman {
  short* count;
  short* symbol;
};
static int puff_decode(struct puff_state* s, const struct puff_huffman* h)
{
  int first = 0;
  int index = 0;
  int bitbuf = s->bitbuf;
  int left = s->bitcnt;
  int code = first = index = 0;
  int len = 1;
  short* next = h->count + 1;
  while (1) {
    while (left--) {
      code |= bitbuf & 1;
      bitbuf >>= 1;
      int count = *next++;
      if (code - count < first) {
        s->bitbuf = bitbuf;
        s->bitcnt = (s->bitcnt - len) & 7;
        return h->symbol[index + (code - first)];
      }
      index += count;
      first += count;
      first <<= 1;
      code <<= 1;
      len++;
    }
    left = (MAXBITS + 1) - len;
    if (left == 0)
      break;
    if (s->incnt == s->inlen)
      longjmp(s->env, 1);
    bitbuf = s->in[s->incnt++];
    if (left > 8)
      left = 8;
  }
  return -10;
}
static int puff_construct(struct puff_huffman* h, const short* length, int n)
{
  int len;
  for (len = 0; len <= MAXBITS; len++)
    h->count[len] = 0;
  int symbol;
  for (symbol = 0; symbol < n; symbol++)
    (h->count[length[symbol]])++;
  if (h->count[0] == n)
    return 0;
  int left = 1;
  for (len = 1; len <= MAXBITS; len++) {
    left <<= 1;
    left -= h->count[len];
    if (left < 0)
      return left;
  }
  short offs[MAXBITS + 1];
  offs[1] = 0;
  for (len = 1; len < MAXBITS; len++)
    offs[len + 1] = offs[len] + h->count[len];
  for (symbol = 0; symbol < n; symbol++)
    if (length[symbol] != 0)
      h->symbol[offs[length[symbol]]++] = symbol;
  return left;
}
static int puff_codes(struct puff_state* s, const struct puff_huffman* lencode,
                      const struct puff_huffman* distcode)
{
  static const short lens[29] = {3,  4,  5,  6,   7,   8,   9,   10,  11, 13,
                                 15, 17, 19, 23,  27,  31,  35,  43,  51, 59,
                                 67, 83, 99, 115, 131, 163, 195, 227, 258};
  static const short lext[29] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2,
                                 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0};
  static const short dists[30] = {
      1,    2,    3,    4,    5,    7,    9,    13,    17,    25,
      33,   49,   65,   97,   129,  193,  257,  385,   513,   769,
      1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
  static const short dext[30] = {0, 0, 0,  0,  1,  1,  2,  2,  3,  3,
                                 4, 4, 5,  5,  6,  6,  7,  7,  8,  8,
                                 9, 9, 10, 10, 11, 11, 12, 12, 13, 13};
  int symbol;
  do {
    symbol = puff_decode(s, lencode);
    if (symbol < 0)
      return symbol;
    if (symbol < 256) {
      if (s->outcnt == s->outlen)
        return 1;
      if (symbol)
        s->out[s->outcnt] = symbol;
      s->outcnt++;
    } else if (symbol > 256) {
      symbol -= 257;
      if (symbol >= 29)
        return -10;
      int len = lens[symbol] + puff_bits(s, lext[symbol]);
      symbol = puff_decode(s, distcode);
      if (symbol < 0)
        return symbol;
      unsigned dist = dists[symbol] + puff_bits(s, dext[symbol]);
      if (dist > s->outcnt)
        return -11;
      if (s->outcnt + len > s->outlen)
        return 1;
      while (len--) {
        if (dist <= s->outcnt && s->out[s->outcnt - dist])
          s->out[s->outcnt] = s->out[s->outcnt - dist];
        s->outcnt++;
      }
    }
  } while (symbol != 256);
  return 0;
}
static int puff_fixed(struct puff_state* s)
{
  static int virgin = 1;
  static short lencnt[MAXBITS + 1], lensym[FIXLCODES];
  static short distcnt[MAXBITS + 1], distsym[MAXDCODES];
  static struct puff_huffman lencode, distcode;
  if (virgin) {
    lencode.count = lencnt;
    lencode.symbol = lensym;
    distcode.count = distcnt;
    distcode.symbol = distsym;
    short lengths[FIXLCODES];
    int symbol;
    for (symbol = 0; symbol < 144; symbol++)
      lengths[symbol] = 8;
    for (; symbol < 256; symbol++)
      lengths[symbol] = 9;
    for (; symbol < 280; symbol++)
      lengths[symbol] = 7;
    for (; symbol < FIXLCODES; symbol++)
      lengths[symbol] = 8;
    puff_construct(&lencode, lengths, FIXLCODES);
    for (symbol = 0; symbol < MAXDCODES; symbol++)
      lengths[symbol] = 5;
    puff_construct(&distcode, lengths, MAXDCODES);
    virgin = 0;
  }
  return puff_codes(s, &lencode, &distcode);
}
static int puff_dynamic(struct puff_state* s)
{
  static const short order[19] = {16, 17, 18, 0, 8,  7, 9,  6, 10, 5,
                                  11, 4,  12, 3, 13, 2, 14, 1, 15};
  int nlen = puff_bits(s, 5) + 257;
  int ndist = puff_bits(s, 5) + 1;
  int ncode = puff_bits(s, 4) + 4;
  if (nlen > MAXLCODES || ndist > MAXDCODES)
    return -3;
  short lengths[MAXCODES];
  int index;
  for (index = 0; index < ncode; index++)
    lengths[order[index]] = puff_bits(s, 3);
  for (; index < 19; index++)
    lengths[order[index]] = 0;
  short lencnt[MAXBITS + 1], lensym[MAXLCODES];
  struct puff_huffman lencode = {lencnt, lensym};
  int err = puff_construct(&lencode, lengths, 19);
  if (err != 0)
    return -4;
  index = 0;
  while (index < nlen + ndist) {
    int symbol;
    int len;
    symbol = puff_decode(s, &lencode);
    if (symbol < 0)
      return symbol;
    if (symbol < 16)
      lengths[index++] = symbol;
    else {
      len = 0;
      if (symbol == 16) {
        if (index == 0)
          return -5;
        len = lengths[index - 1];
        symbol = 3 + puff_bits(s, 2);
      } else if (symbol == 17)
        symbol = 3 + puff_bits(s, 3);
      else
        symbol = 11 + puff_bits(s, 7);
      if (index + symbol > nlen + ndist)
        return -6;
      while (symbol--)
        lengths[index++] = len;
    }
  }
  if (lengths[256] == 0)
    return -9;
  err = puff_construct(&lencode, lengths, nlen);
  if (err && (err < 0 || nlen != lencode.count[0] + lencode.count[1]))
    return -7;
  short distcnt[MAXBITS + 1], distsym[MAXDCODES];
  struct puff_huffman distcode = {distcnt, distsym};
  err = puff_construct(&distcode, lengths + nlen, ndist);
  if (err && (err < 0 || ndist != distcode.count[0] + distcode.count[1]))
    return -8;
  return puff_codes(s, &lencode, &distcode);
}
static int puff(unsigned char* dest, unsigned long* destlen,
                const unsigned char* source, unsigned long sourcelen)
{
  struct puff_state s = {
      .out = dest,
      .outlen = *destlen,
      .outcnt = 0,
      .in = source,
      .inlen = sourcelen,
      .incnt = 0,
      .bitbuf = 0,
      .bitcnt = 0,
  };
  int err;
  if (setjmp(s.env) != 0)
    err = 2;
  else {
    int last;
    do {
      last = puff_bits(&s, 1);
      int type = puff_bits(&s, 2);
      err = type == 0 ? puff_stored(&s)
                      : (type == 1 ? puff_fixed(&s)
                                   : (type == 2 ? puff_dynamic(&s) : -1));
      if (err != 0)
        break;
    } while (!last);
  }
  *destlen = s.outcnt;
  return err;
}

//% END CODE DERIVED FROM puff.{c,h}

#define ZLIB_HEADER_WIDTH 2

static int puff_zlib_to_file(const unsigned char* source,
                             unsigned long sourcelen, int dest_fd)
{
  if (sourcelen < ZLIB_HEADER_WIDTH)
    return 0;
  source += ZLIB_HEADER_WIDTH;
  sourcelen -= ZLIB_HEADER_WIDTH;
  const unsigned long max_destlen = 132 << 20;
  void* ret = mmap(0, max_destlen, PROT_WRITE | PROT_READ,
                   MAP_PRIVATE | MAP_ANON, -1, 0);
  if (ret == MAP_FAILED)
    return -1;
  unsigned char* dest = (unsigned char*)ret;
  unsigned long destlen = max_destlen;
  int err = puff(dest, &destlen, source, sourcelen);
  if (err) {
    munmap(dest, max_destlen);
    errno = -err;
    return -1;
  }
  if (write(dest_fd, dest, destlen) != (ssize_t)destlen) {
    munmap(dest, max_destlen);
    return -1;
  }
  return munmap(dest, max_destlen);
}

static int setup_loop_device(unsigned char* data, unsigned long size,
                             const char* loopname, int* loopfd_p)
{
  int err = 0, loopfd = -1;
  int memfd = syscall(__NR_memfd_create, "syzkaller", 0);
  if (memfd == -1) {
    err = errno;
    goto error;
  }
  if (puff_zlib_to_file(data, size, memfd)) {
    err = errno;
    goto error_close_memfd;
  }
  loopfd = open(loopname, O_RDWR);
  if (loopfd == -1) {
    err = errno;
    goto error_close_memfd;
  }
  if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
    if (errno != EBUSY) {
      err = errno;
      goto error_close_loop;
    }
    ioctl(loopfd, LOOP_CLR_FD, 0);
    usleep(1000);
    if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
      err = errno;
      goto error_close_loop;
    }
  }
  close(memfd);
  *loopfd_p = loopfd;
  return 0;

error_close_loop:
  close(loopfd);
error_close_memfd:
  close(memfd);
error:
  errno = err;
  return -1;
}

static long syz_mount_image(volatile long fsarg, volatile long dir,
                            volatile long flags, volatile long optsarg,
                            volatile long change_dir,
                            volatile unsigned long size, volatile long image)
{
  unsigned char* data = (unsigned char*)image;
  int res = -1, err = 0, loopfd = -1, need_loop_device = !!size;
  char* mount_opts = (char*)optsarg;
  char* target = (char*)dir;
  char* fs = (char*)fsarg;
  char* source = NULL;
  char loopname[64];
  if (need_loop_device) {
    memset(loopname, 0, sizeof(loopname));
    snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid);
    if (setup_loop_device(data, size, loopname, &loopfd) == -1)
      return -1;
    source = loopname;
  }
  mkdir(target, 0777);
  char opts[256];
  memset(opts, 0, sizeof(opts));
  if (strlen(mount_opts) > (sizeof(opts) - 32)) {
  }
  strncpy(opts, mount_opts, sizeof(opts) - 32);
  if (strcmp(fs, "iso9660") == 0) {
    flags |= MS_RDONLY;
  } else if (strncmp(fs, "ext", 3) == 0) {
    bool has_remount_ro = false;
    char* remount_ro_start = strstr(opts, "errors=remount-ro");
    if (remount_ro_start != NULL) {
      char after = *(remount_ro_start + strlen("errors=remount-ro"));
      char before = remount_ro_start == opts ? '\0' : *(remount_ro_start - 1);
      has_remount_ro = ((before == '\0' || before == ',') &&
                        (after == '\0' || after == ','));
    }
    if (strstr(opts, "errors=panic") || !has_remount_ro)
      strcat(opts, ",errors=continue");
  } else if (strcmp(fs, "xfs") == 0) {
    strcat(opts, ",nouuid");
  }
  res = mount(source, target, fs, flags, opts);
  if (res == -1) {
    err = errno;
    goto error_clear_loop;
  }
  res = open(target, O_RDONLY | O_DIRECTORY);
  if (res == -1) {
    err = errno;
    goto error_clear_loop;
  }
  if (change_dir) {
    res = chdir(target);
    if (res == -1) {
      err = errno;
    }
  }

error_clear_loop:
  if (need_loop_device) {
    ioctl(loopfd, LOOP_CLR_FD, 0);
    close(loopfd);
  }
  errno = err;
  return res;
}

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)) {
  }
}

static void loop();

static void sandbox_common()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setsid();
  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();
  sandbox_common();
  drop_caps();
  if (unshare(CLONE_NEWNET)) {
  }
  write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
  setup_binderfs();
  loop();
  exit(1);
}

#define FS_IOC_SETFLAGS _IOW('f', 2, long)
static void remove_dir(const char* dir)
{
  int iter = 0;
  DIR* dp = 0;
retry:
  while (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) {
  }
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exit(1);
    }
    exit(1);
  }
  struct dirent* ep = 0;
  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);
    while (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) {
    }
    struct stat st;
    if (lstat(filename, &st))
      exit(1);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      if (unlink(filename) == 0)
        break;
      if (errno == EPERM) {
        int fd = open(filename, O_RDONLY);
        if (fd != -1) {
          long flags = 0;
          if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
          }
          close(fd);
          continue;
        }
      }
      if (errno == EROFS) {
        break;
      }
      if (errno != EBUSY || i > 100)
        exit(1);
      if (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW))
        exit(1);
    }
  }
  closedir(dp);
  for (int i = 0;; i++) {
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EPERM) {
        int fd = open(dir, O_RDONLY);
        if (fd != -1) {
          long flags = 0;
          if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
          }
          close(fd);
          continue;
        }
      }
      if (errno == EROFS) {
        break;
      }
      if (errno == EBUSY) {
        if (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW))
          exit(1);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    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 reset_loop()
{
  char buf[64];
  snprintf(buf, sizeof(buf), "/dev/loop%llu", procid);
  int loopfd = open(buf, O_RDWR);
  if (loopfd != -1) {
    ioctl(loopfd, LOOP_CLR_FD, 0);
    close(loopfd);
  }
}

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

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

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
  int iter = 0;
  for (;; iter++) {
    char cwdbuf[32];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      exit(1);
    reset_loop();
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      if (chdir(cwdbuf))
        exit(1);
      setup_test();
      execute_one();
      close_fds();
      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;
    }
    remove_dir(cwdbuf);
  }
}

void execute_one(void)
{
  memcpy((void*)0x20000540, "ext4\000", 5);
  memcpy((void*)0x20000580, "./file0\000", 8);
  memcpy((void*)0x20000000,
         "\x00\xf7\xf3\x9e\xf9\xcd\x1c\x6a\x04\x3f\xd7\x8a\xa7\xf9\xce\xb4\xe5"
         "\xc2\xc4\x3d\xa9\xd7\x96\x18\xdd\x18\xc1\x68\x98\x9c\x2d\xc4\xb4\x12"
         "\xca\x72\x6b\x49\x63\x9a\x98\x2c\xdf\x09\x41\x2c\x67\xd4\x7a\xc4\x0b"
         "\xa2\x43\x93\x7f\x7d\xe1\xf5\x33\xf3\xfa\xf1\xb1\xc0\x6d\x75\xa8\x9a"
         "\x1a\xfa\x46\x79\x71\xac\x77\x27\x84\x46\x28\x3e\xf9\x0c\xba\xcd\x7d"
         "\x21\x9b\x47\x63\x46\xfd\x12\x2c\xed\xa1\x50\x65\xe1\xa1\xb1\xdf\xee"
         "\x4f\x0a\x1c\x59\xac\x58\xc8\x1e\xe7\x58\x34\x10\x8b\x6b\xb2\x06",
         118);
  memcpy(
      (void*)0x200005c0,
      "\x78\x9c\xec\xdd\xcf\x6b\x1c\x55\x1c\x00\xf0\xef\x6c\x92\x36\xb6\x6a\x5b"
      "\x28\x45\x3d\x68\xa0\xa0\x85\xda\x4d\x93\xf8\xa3\x82\x87\xf6\x28\x5a\x2c"
      "\xe8\xcd\x43\xbb\x24\xdb\x50\xb2\xe9\x96\xec\xa6\x34\x69\xc1\xf6\x60\x2f"
      "\x5e\xa4\x08\x22\x16\x44\xf0\xea\xdd\x63\xf1\x1f\xf0\xe0\x1f\xe0\xa9\xa0"
      "\x85\x22\x25\x78\xf1\xe0\xca\x6c\x66\xd3\x6d\xb2\x9b\xac\x49\xb6\xbb\x74"
      "\x3f\x1f\x98\xe6\xbd\x99\xd9\x7d\xef\x3b\xf3\xde\xdb\x37\x3b\x53\x36\x80"
      "\x81\x35\x96\xfe\x93\x8b\x78\x39\x22\xbe\x4a\x22\x0e\x34\x6d\x1b\x8e\x6c"
      "\xe3\xd8\xea\x7e\x2b\x8f\x6e\x4c\xa7\x4b\x12\xb5\xda\x27\x7f\x25\x91\x64"
      "\xeb\x1a\xfb\x27\xd9\xdf\xfd\x59\xe6\xa5\x88\xf8\xe5\x8b\x88\xe3\xb9\x8d"
      "\xe5\x56\x96\x96\xe7\x0a\xa5\x52\x71\x21\xcb\x8f\x57\xe7\xaf\x8c\x57\x96"
      "\x96\x4f\x5c\x9a\x2f\xcc\x16\x67\x8b\x97\x27\xa7\xa6\x4e\xbd\x3d\x35\xf9"
      "\xde\xbb\xef\xec\x46\x98\xd7\x0f\xad\xfe\xfd\xf6\xe3\x7b\x1f\x9c\xfa\xf2"
      "\xe8\xca\x37\x3f\x3d\x38\x74\x27\x89\xd3\xf1\x6f\xad\x56\x8b\x75\x71\xec"
      "\x96\xb1\x18\xcb\x8e\xc9\x48\x9c\x5e\xb7\x6d\x62\xb7\x0b\xeb\xb1\xa4\xd7"
      "\x15\x60\x5b\x86\xb2\x7e\x3e\x12\xe9\x18\x70\x20\x86\xb2\x5e\x0f\x3c\xfb"
      "\x3e\x8f\x88\x1a\x30\xa0\x12\xfd\x1f\x06\x54\x63\x1e\xd0\xb8\xb6\xef\xc6"
      "\x75\x70\x3f\x7b\x78\x26\xe2\xb3\x5c\xab\xf8\x87\x57\xbf\x1b\x89\xd1\xfa"
      "\xb5\xd1\xbe\x95\xe4\x89\x2b\xa3\xf4\x7a\xf7\xe0\x2e\x94\x3f\x1a\x11\x3f"
      "\xff\x79\xf7\x4e\xba\x44\x97\xbe\x87\x00\x68\xe5\xe6\xad\x88\x38\x39\x3c"
      "\xbc\x71\xfc\x4b\xb2\xf1\x6f\xfb\x4e\x76\xb0\xcf\xfa\x32\x8c\x7f\xf0\xf4"
      "\xdc\x3b\x13\x11\x6f\xb6\x9a\xff\xe4\xd6\xe6\x3f\x91\xcd\x7f\x9a\xe7\x8b"
      "\xfb\x5b\xf4\xdd\xed\xd8\xba\xff\xe7\x1e\xec\x42\x31\x6d\xa5\xf3\xbf\xf7"
      "\x5b\xce\x7f\xd7\x6e\x5a\x1d\x1c\xca\x72\x2f\xd4\xe7\x7c\x23\xc9\xc5\x4b"
      "\xa5\x62\x3a\xb6\xbd\x18\x11\xc7\x62\x64\x6f\x9a\xdf\xec\x7e\xce\xa9\x95"
      "\xfb\xb5\x76\xdb\xc6\x9a\xe6\x7f\xe9\x92\x96\xdf\x98\x0b\x66\xf5\x78\x30"
      "\xbc\xf7\xc9\xd7\xcc\x14\xaa\x85\x9d\xc4\xdc\xec\xe1\xad\x88\x57\x86\x5b"
      "\xc5\x9f\xac\x9d\xff\xa4\xc5\xfc\x37\x3d\x1e\xe7\x3a\x2c\xe3\x48\xf1\xee"
      "\xab\xed\xb6\x6d\x1d\xff\x66\x7e\xef\xb0\x06\xed\xd5\x7e\x88\x78\xa3\xf9"
      "\xfc\xff\xd6\xd8\xf2\xf8\x8e\x56\xb2\xf9\xfd\xc9\xf1\x7a\x7b\x18\x6f\xb4"
      "\x8a\x8d\xfe\xbe\x7d\xe4\xd7\x76\xe5\xef\x2c\xfe\x9d\x4b\xcf\xff\xbe\x96"
      "\xed\x7f\x2d\xfe\x83\x49\xf3\xfd\xda\xca\xd6\xef\xf9\xe3\xba\xfc\xf7\xa3"
      "\xff\x14\xdb\xed\xbb\xdd\xf6\xbf\x27\xf9\xb4\x9e\xde\x93\xad\xbb\x56\xa8"
      "\x56\x17\x26\xd2\xdc\x47\x1b\xd7\x4f\x3e\x7e\x6d\x23\xbf\xba\xff\x6a\xfc"
      "\xc7\x8e\xa6\xf1\xbf\xd6\x76\xfc\x6b\xd5\xfe\x4f\x47\xc4\x85\x27\x8f\x53"
      "\x5b\xb7\x0f\xdf\xbe\xb0\xfd\xf8\xbb\x2b\x8d\x7f\xe6\x7f\x9d\xff\x8e\x13"
      "\x31\x9a\x25\xee\x7f\x78\xfd\xbb\x76\xe5\x77\x76\xfe\xdf\xaa\xa7\x8e\x65"
      "\x6b\x3a\x19\xff\x3a\xad\xe9\x4e\x8e\x1d\x00\x00\x00\x00\x00\x00\xf4\x9b"
      "\x5c\x44\x3c\x1f\x49\x2e\xbf\x96\xce\xe5\xf2\xf9\xd5\xe7\x3b\x0e\xc7\xbe"
      "\x5c\xa9\x5c\xa9\x1e\xbf\x58\x5e\xbc\x3c\x93\x6e\xab\x3f\xff\x90\x6b\xdc"
      "\xe9\x3e\xd0\xf4\x3c\xc4\x44\xf6\x3c\x6c\x23\x3f\xb9\x2e\x3f\x15\x11\x87"
      "\x22\xe2\xeb\xa1\xe7\xea\xf9\xfc\x74\xb9\x34\xd3\xeb\xe0\x01\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xa0\x4f\xec\x6f\xf3\xff\xff"
      "\x53\x7f\x0c\xf5\xba\x76\x40\xd7\xf9\xc9\x6f\x18\x5c\x8f\xfb\xff\x48\x4f"
      "\xeb\x01\x3c\x7d\x3e\xff\x61\x70\xe9\xff\x30\xb8\xf4\x7f\x18\x5c\xfa\x3f"
      "\x0c\x2e\xfd\x1f\x06\xd7\x36\xfa\xff\xeb\xdd\xa8\x07\xf0\xf4\xf9\xfc\x87"
      "\xc1\xb5\xae\xff\x8f\x6e\xba\x73\xd2\xdd\xba\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xc0\x33\xe0\xdc"
      "\xd9\xb3\xe9\x52\x5b\x79\x74\x63\x3a\xcd\xcf\x5c\x5d\x5a\x9c\x2b\x5f\x3d"
      "\x31\x53\xac\xcc\xe5\xe7\x17\xa7\xf3\xd3\xe5\x85\x2b\xf9\xd9\x72\x79\xb6"
      "\x54\xcc\x4f\x97\xe7\xb7\x7a\xbf\x52\xb9\x7c\x65\x62\x32\x16\xaf\x8d\x57"
      "\x8b\x95\xea\x78\x65\x69\xf9\xfc\x7c\x79\xf1\x72\xf5\xfc\xa5\xf9\xc2\x6c"
      "\xf1\x7c\xd1\x0f\x0c\x03\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\xc0\x46\x95\xa5\xe5\xb9\x42\xa9\x54\x5c\x18\xc4\x44\x12\x71\x73"
      "\x93\x7d\xf6\x66\xc7\xa8\x1f\xaa\xda\x85\x44\x12\x49\x3d\xbc\x7e\xa9\x4f"
      "\xa3\x49\xf6\x4b\x7d\x3a\x49\xa4\x4d\xa4\x0f\xaa\xd1\x8d\x44\xaf\x46\x24"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd8\xe8\xbf\x00\x00"
      "\x00\xff\xff\xec\xd9\x32\x7d",
      1429);
  syz_mount_image(/*fs=*/0x20000540, /*dir=*/0x20000580, /*flags=*/0xd,
                  /*opts=*/0x20000000, /*chdir=*/1, /*size=*/0x594,
                  /*img=*/0x200005c0);
}
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);
  for (procid = 0; procid < 6; procid++) {
    if (fork() == 0) {
      use_temporary_dir();
      do_sandbox_none();
    }
  }
  sleep(1000000);
  return 0;
}



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