INFO: task kworker/u8:2:40 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:2    state:D stack:21312 pid:40    tgid:40    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
 f2fs_down_write fs/f2fs/f2fs.h:2407 [inline]
 f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
 f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2104
 f2fs_balance_fs_bg+0x574/0x9d0 fs/f2fs/segment.c:545
 f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2251
 do_writepages+0x32e/0x550 mm/page-writeback.c:2554
 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
 writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2042
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2229
 wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
 wb_do_writeback fs/fs-writeback.c:2386 [inline]
 wb_workfn+0xb52/0xf60 fs/fs-writeback.c:2414
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u8:1/13:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc90000127c40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc90000127c40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
1 lock held by khungtaskd/38:
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:2/40:
 #0: ffff88801e6d7138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff88801e6d7138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc90000b17c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc90000b17c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
 #2: ffff88802933e0d0 (&type->s_umount_key#80){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
 #3: ffff888036271a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2407 [inline]
 #3: ffff888036271a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
 #3: ffff888036271a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2104
3 locks held by kworker/u8:4/68:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc9000153fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc9000153fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
 #2: ffffffff8f15a3b8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by getty/5552:
 #0: ffff88803699d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:6/5958:
 #0: ffff888019c03d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c03d38 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc90004f47c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc90004f47c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
 #2: ffff888020ae4260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
2 locks held by kworker/u8:12/8768:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc90004897c40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc90004897c40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
2 locks held by kworker/0:7/8980:
4 locks held by kworker/u8:15/9404:
9 locks held by syz-executor/18566:
7 locks held by kworker/0:3/21073:
3 locks held by syz.9.1293/21358:
1 lock held by syz-executor/22028:
4 locks held by syz-executor/25578:
1 lock held by syz.8.1732/26435:
 #0: ffff888063a6e0d0 (&type->s_umount_key#79/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
4 locks held by syz.5.1735/26455:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 22028 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:228 [inline]
RIP: 0010:unwind_next_frame+0x214/0x23c0 arch/x86/kernel/unwind_orc.c:510
Code: ef 08 8b 15 9e 91 09 0c 8d 42 ff 44 39 f8 0f 86 78 04 00 00 44 89 f8 4c 8d 2c 85 80 1e 9b 90 4c 89 e8 48 c1 e8 03 0f b6 04 28 <84> c0 48 89 eb 0f 85 25 1c 00 00 45 8b 6d 00 44 89 f8 ff c0 48 8d
RSP: 0018:ffffc9000fb17118 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000080000000
RDX: 00000000000a2694 RSI: ffffffff8ba64860 RDI: ffffffff8ba64820
RBP: dffffc0000000000 R08: ffffffff81765a15 R09: ffffffff8ddcd780
R10: ffffc9000fb17238 R11: ffffffff81af6260 R12: ffffffff81af61f8
R13: ffffffff909ddc04 R14: ffffc9000fb171e8 R15: 000000000000af61
FS:  000055557ce48500(0000) GS:ffff888126340000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5077fd3a10 CR3: 00000000577d0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x124/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 free_unref_folios+0xe7b/0x1c70 mm/page_alloc.c:3040
 folios_put_refs+0x56f/0x680 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x52c/0x1660 mm/shmem.c:1149
 shmem_truncate_range mm/shmem.c:1277 [inline]
 shmem_evict_inode+0x240/0x9e0 mm/shmem.c:1407
 evict+0x61e/0xb10 fs/inode.c:846
 __dentry_kill+0x1a2/0x5e0 fs/dcache.c:670
 finish_dput+0xc9/0x480 fs/dcache.c:879
 __fput+0x6a3/0xa90 fs/file_table.c:477
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff17596cfce
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffdb96ba468 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000055557ce48500 RCX: 00007ff17596cfce
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffdb96ba50c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000046
R13: 00000000000927c0 R14: 000000000010ab67 R15: 00007ffdb96ba560
 </TASK>