INFO: task kworker/u8:1:13 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:1    state:D stack:20488 pid:13    tgid:13    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:3)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5253 [inline]
 __schedule+0x172e/0x4c90 kernel/sched/core.c:6861
 __schedule_loop kernel/sched/core.c:6943 [inline]
 rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7239
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244
 f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
 f2fs_issue_checkpoint+0x3a8/0x610 fs/f2fs/checkpoint.c:1893
 f2fs_balance_fs_bg+0x54b/0x9c0 fs/f2fs/segment.c:544
 f2fs_write_node_pages+0x146/0x6e0 fs/f2fs/node.c:2218
 do_writepages+0x32e/0x550 mm/page-writeback.c:2598
 __writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737
 writeback_sb_inodes+0x8c8/0x1840 fs/fs-writeback.c:2030
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107
 wb_writeback+0x43f/0xaa0 fs/fs-writeback.c:2218
 wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
 wb_do_writeback fs/fs-writeback.c:2375 [inline]
 wb_workfn+0xad7/0xee0 fs/fs-writeback.c:2403
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x52d/0xa60 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:
4 locks held by kworker/u8:1/13:
 #0: ffff88801caa9938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
 #0: ffff88801caa9938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3346
 #1: ffffc90000127b80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
 #1: ffffc90000127b80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3346
 #2: ffff888010f660d0 (&type->s_umount_key#82){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
 #3: ffff88804c1f99f8 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
 #3: ffff88804c1f99f8 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x3a8/0x610 fs/f2fs/checkpoint.c:1893
1 lock held by khungtaskd/38:
 #0: ffffffff8d5ae320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8d5ae320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8d5ae320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:7/1111:
 #0: ffff88813ff69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
 #0: ffff88813ff69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3346
 #1: ffffc9000521fb80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
 #1: ffffc9000521fb80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3346
 #2: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
5 locks held by kworker/u8:16/1537:
 #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
 #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3346
 #1: ffffc9000626fb80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
 #1: ffffc9000626fb80 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3346
 #2: ffffffff8e87af20 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7b0 net/core/net_namespace.c:669
 #3: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1c/0x1d0 drivers/net/wireguard/device.c:419
 #4: ffff888032d057b8 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_netns_pre_exit+0xb0/0x1d0 drivers/net/wireguard/device.c:424
2 locks held by dhcpcd/5472:
 #0: ffffffff8e8f01e0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:17926
2 locks held by getty/5564:
 #0: ffff88823bf280a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
5 locks held by syz.3.504/8571:
1 lock held by syz-executor/10567:
 #0: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064
2 locks held by syz-executor/10575:
 #0: ffffffff8e0080c0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e0080c0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e0080c0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064
1 lock held by syz-executor/10592:
 #0: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064
2 locks held by syz-executor/10625:
 #0: ffffffff8e0080c0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e0080c0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e0080c0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064
2 locks held by syz-executor/10670:
 #0: ffffffff8ed95b00 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ed95b00 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8ed95b00 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8e887f38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf3c/0xf80 kernel/hung_task.c:495
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x52d/0xa60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 8571 Comm: syz.3.504 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__kasan_check_read+0xa/0x20 mm/kasan/shadow.c:31
Code: 31 ed eb cf cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 89 f6 48 8b 0c 24 <31> d2 e9 ef e4 ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffc90005b9eed8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81c764f8
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ed94370
RBP: ffffc90005b9ef90 R08: ffff88804c1f834b R09: 1ffff1100983f069
R10: dffffc0000000000 R11: ffffed100983f06a R12: dffffc0000000000
R13: ffff88804c1f8348 R14: ffff88804c1f8348 R15: 1ffff92000b73de0
FS:  00007f406c97e6c0(0000) GS:ffff888126e88000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f88add4098b CR3: 0000000024726000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 cpumask_test_cpu include/linux/cpumask.h:646 [inline]
 cpu_online include/linux/cpumask.h:1205 [inline]
 trace_irq_enable+0x28/0x100 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:73
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
 _raw_spin_unlock_irqrestore+0x85/0x110 kernel/locking/spinlock.c:194
 unlock_rt_mutex_safe kernel/locking/rtmutex.c:344 [inline]
 rt_mutex_slowunlock+0x493/0x8a0 kernel/locking/rtmutex.c:1454
 f2fs_up_write fs/f2fs/f2fs.h:2319 [inline]
 f2fs_unlock_all fs/f2fs/f2fs.h:2379 [inline]
 block_operations fs/f2fs/checkpoint.c:1262 [inline]
 f2fs_write_checkpoint+0x9c7/0x2440 fs/f2fs/checkpoint.c:1678
 f2fs_issue_checkpoint+0x3b8/0x610 fs/f2fs/checkpoint.c:1894
 f2fs_do_sync_file+0x85c/0x1850 fs/f2fs/file.c:352
 generic_write_sync include/linux/fs.h:2617 [inline]
 f2fs_file_write_iter+0x740/0x2420 fs/f2fs/file.c:5266
 do_iter_readv_writev+0x635/0x8d0 fs/read_write.c:-1
 vfs_writev+0x323/0x970 fs/read_write.c:1057
 do_pwritev fs/read_write.c:1153 [inline]
 __do_sys_pwritev2 fs/read_write.c:1211 [inline]
 __se_sys_pwritev2+0x17c/0x2a0 fs/read_write.c:1202
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f406e71f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f406c97e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f406e975fa0 RCX: 00007f406e71f749
RDX: 0000000000000001 RSI: 0000200000000680 RDI: 0000000000000007
RBP: 00007f406e7a3f91 R08: 0000000000000006 R09: 0000000000000021
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f406e976038 R14: 00007f406e975fa0 R15: 00007ffc35858a28
 </TASK>