INFO: task kworker/u4:13:9854 blocked for more than 143 seconds.
      Not tainted 5.15.102-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:13   state:D stack:23416 pid: 9854 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:1)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5023 [inline]
 __schedule+0x1348/0x4610 kernel/sched/core.c:6369
 schedule+0x11b/0x1f0 kernel/sched/core.c:6452
 rwsem_down_write_slowpath+0xebb/0x15c0 kernel/locking/rwsem.c:1157
 __down_write_common kernel/locking/rwsem.c:1284 [inline]
 __down_write kernel/locking/rwsem.c:1293 [inline]
 down_write+0x164/0x170 kernel/locking/rwsem.c:1542
 f2fs_balance_fs+0x4d4/0x6a0 fs/f2fs/segment.c:529
 f2fs_write_inode+0x4c3/0x540 fs/f2fs/inode.c:725
 write_inode fs/fs-writeback.c:1475 [inline]
 __writeback_single_inode+0x808/0x1210 fs/fs-writeback.c:1680
 writeback_sb_inodes+0xbd8/0x1ac0 fs/fs-writeback.c:1905
 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:1976
 wb_writeback+0x4cc/0xeb0 fs/fs-writeback.c:2081
 wb_check_old_data_flush fs/fs-writeback.c:2181 [inline]
 wb_do_writeback fs/fs-writeback.c:2234 [inline]
 wb_workfn+0xc42/0x10e0 fs/fs-writeback.c:2263
 process_one_work+0x90d/0x1270 kernel/workqueue.c:2306
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2453
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 <unknown>:298
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91c2a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3270:
 #0: ffff88814bc9a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002bb32e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1da0 drivers/tty/n_tty.c:2147
4 locks held by kworker/u4:13/9854:
 #0: ffff88801498c138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x794/0x1270 kernel/workqueue.c:2279
 #1: ffffc900046f7d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7da/0x1270 kernel/workqueue.c:2281
 #2: ffff88807e1460e0 (&type->s_umount_key#61){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:418
 #3: ffff888030a35108 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x4d4/0x6a0 fs/f2fs/segment.c:529
2 locks held by syz-executor.1/27237:
2 locks held by syz-executor.0/31066:
 #0: ffff88807e1460e0 (&type->s_umount_key#61){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:694
 #1: ffff88802f3ba7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff88802f3ba7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2743

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb 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+0xf54/0xfa0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 <unknown>:298
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3755 Comm: kworker/u4:8 Not tainted 5.15.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0x1a8/0x1ff0
Code: 20 0a 00 00 83 fd 30 0f 87 88 1b 00 00 48 8d 44 ad 00 48 8d 5c c3 f8 48 89 d8 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 8b 16 00 00 <48> 89 e8 48 83 bc 24 c0 00 00 00 00 0f 84 f4 00 00 00 8b 2b 89 e9
RSP: 0018:ffffc9000411f900 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88801c66c468 RCX: ffffffff913a9f03
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff888079abc358
RBP: 0000000000000002 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff88801c66ba00 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fb139ff5b0 CR3: 000000007e753000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:368 [inline]
 batadv_nc_purge_paths+0xe8/0x3b0 net/batman-adv/network-coding.c:446
 batadv_nc_worker+0x30b/0x5b0 net/batman-adv/network-coding.c:726
 process_one_work+0x90d/0x1270 kernel/workqueue.c:2306
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2453
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 <unknown>:298
 </TASK>