INFO: task kworker/u4:8:1036 blocked for more than 143 seconds.
      Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:8    state:D stack:19352 pid:1036  tgid:1036  ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x184f/0x4c30 kernel/sched/core.c:6693
 __schedule_loop kernel/sched/core.c:6770 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6785
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6842
 rwsem_down_write_slowpath+0xeee/0x13b0 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1d7/0x220 kernel/locking/rwsem.c:1578
 f2fs_down_write fs/f2fs/f2fs.h:2199 [inline]
 f2fs_balance_fs+0x5b0/0x7a0 fs/f2fs/segment.c:448
 f2fs_write_inode+0x3a0/0x4d0 fs/f2fs/inode.c:787
 write_inode fs/fs-writeback.c:1503 [inline]
 __writeback_single_inode+0x711/0x10d0 fs/fs-writeback.c:1723
 writeback_sb_inodes+0x80c/0x1370 fs/fs-writeback.c:1954
 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2025
 wb_writeback+0x42f/0xbd0 fs/fs-writeback.c:2136
 wb_check_background_flush fs/fs-writeback.c:2206 [inline]
 wb_do_writeback fs/fs-writeback.c:2294 [inline]
 wb_workfn+0xc58/0x1090 fs/fs-writeback.c:2321
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/25:
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
4 locks held by kworker/u4:8/1036:
 #0: ffff88801dca1148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801dca1148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc900023ffd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc900023ffd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffff88801ce260e0 (&type->s_umount_key#43){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562
 #3: ffff8880437d9350 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2199 [inline]
 #3: ffff8880437d9350 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x5b0/0x7a0 fs/f2fs/segment.c:448
2 locks held by getty/5108:
 #0: ffff8880007790a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
5 locks held by syz-executor159/5326:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25 Comm: khungtaskd Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>