INFO: task kworker/u4:9:3870 blocked for more than 143 seconds.
      Not tainted 5.15.159-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:9    state:D stack:20824 pid: 3870 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6518
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 exfat_write_inode+0x65/0x110 fs/exfat/inode.c:87
 write_inode fs/fs-writeback.c:1495 [inline]
 __writeback_single_inode+0x644/0xe30 fs/fs-writeback.c:1705
 writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930
 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001
 wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106
 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
 wb_do_writeback fs/fs-writeback.c:2259 [inline]
 wb_workfn+0xc55/0x1130 fs/fs-writeback.c:2288
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3260:
 #0: ffff888024ea8098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000249c2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:9/3870:
 #0: ffff888142394938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003507d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff88807722e0e0 (&type->s_umount_key#51){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:418
 #3: ffff88807722c0e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_write_inode+0x65/0x110 fs/exfat/inode.c:87
3 locks held by syz-executor.4/4494:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.159-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4494 Comm: syz-executor.4 Not tainted 5.15.159-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:__sanitizer_cov_trace_switch+0x3f/0xe0
Code: f8 07 0f 87 ac 00 00 00 b9 8b 00 00 00 0f a3 c1 0f 83 9e 00 00 00 4c 8b 16 4d 85 d2 0f 84 92 00 00 00 4c 8b 04 c5 40 e9 8e 8a <4c> 8b 4c 24 20 65 4c 8b 1d 54 0e 82 7e 31 d2 eb 08 48 ff c2 49 39
RSP: 0018:ffffc90002eb7760 EFLAGS: 00000206
RAX: 0000000000000003 RBX: 0000000000000005 RCX: 000000000000008b
RDX: 0000000000000001 RSI: ffffffff8cad5ba0 RDI: 0000000000000005
RBP: 1ffff920005d6f38 R08: 0000000000000005 R09: ffffed100ecf960d
R10: 0000000000000003 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000005 R14: ffff8880767cb000 R15: ffffc90002eb79c0
FS:  00005555555e6480(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeae7fd428 CR3: 000000005d11e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 exfat_ent_get+0x1f3/0x400 fs/exfat/fatent.c:104
 exfat_readdir fs/exfat/dir.c:184 [inline]
 exfat_iterate+0xda2/0x34a0 fs/exfat/dir.c:258
 iterate_dir+0x224/0x570
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f92c00973e3
Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 42 8b fa ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 b0 ff ff ff f7 d8
RSP: 002b:00007fff81defcc8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00005555555ef970 RCX: 00007f92c00973e3
RDX: 0000000000008000 RSI: 00005555555ef970 RDI: 0000000000000005
RBP: 00005555555ef944 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000293 R12: ffffffffffffffb0
R13: 0000000000000010 R14: 00005555555ef940 R15: 0000000000000005
 </TASK>