INFO: task kworker/u8:4:66 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:21512 pid:66    tgid:66    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
 f2fs_down_write fs/f2fs/f2fs.h:2411 [inline]
 f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:180
 f2fs_issue_checkpoint+0x414/0x6f0 fs/f2fs/checkpoint.c:2095
 f2fs_balance_fs_bg+0x571/0x9d0 fs/f2fs/segment.c:545
 f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2257
 do_writepages+0x338/0x560 mm/page-writeback.c:2571
 __writeback_single_inode+0x12e/0xf90 fs/fs-writeback.c:1787
 writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2079
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2155
 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2266
 wb_check_old_data_flush fs/fs-writeback.c:2370 [inline]
 wb_do_writeback fs/fs-writeback.c:2449 [inline]
 wb_workfn+0xc98/0x10f0 fs/fs-writeback.c:2477
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: lockdep is turned off.
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 05/09/2026
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:162 [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:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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: 14457 Comm: syz.3.835 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:vsnprintf+0x96/0xef0 lib/vsprintf.c:2884
Code: c1 ff ff ff ff 48 0f 43 c8 48 89 4c 24 08 49 0f 43 f7 48 89 74 24 40 48 89 d8 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 06 0e 00 00 <0f> b6 2b 31 ff 89 ee e8 de e3 a7 f6 85 ed 4c 89 64 24 48 0f 84 ff
RSP: 0018:ffffc90004737328 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8b962b20 RCX: ffffc9000473767d
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 000000007fffffff
RBP: ffffc900047374b8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90004737420 R11: fffff520008e6e87 R12: ffffc9000473767d
R13: ffffc90004737420 R14: ffffc9000473767d R15: 0000000000000000
FS:  00007f52159566c0(0000) GS:ffff888126144000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33704fb000 CR3: 000000003c6ae000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 va_format lib/vsprintf.c:1725 [inline]
 pointer+0xa12/0x1120 lib/vsprintf.c:2573
 vsnprintf+0x626/0xef0 lib/vsprintf.c:2949
 vprintk_store+0x3c1/0xda0 kernel/printk/printk.c:2307
 vprintk_emit+0x192/0x560 kernel/printk/printk.c:2455
 _printk+0xdd/0x130 kernel/printk/printk.c:2504
 _btrfs_printk+0x29a/0x320 fs/btrfs/messages.c:236
 open_ctree+0xaf7/0x41c0 fs/btrfs/disk-io.c:3404
 btrfs_fill_super fs/btrfs/super.c:982 [inline]
 btrfs_get_tree_super fs/btrfs/super.c:1971 [inline]
 btrfs_get_tree_subvol fs/btrfs/super.c:2114 [inline]
 btrfs_get_tree+0x1084/0x1980 fs/btrfs/super.c:2148
 vfs_get_tree+0x92/0x2a0 fs/super.c:1694
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x319/0xdc0 fs/namespace.c:3841
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4367
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f52176fe0ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5215955e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5215955ee0 RCX: 00007f52176fe0ca
RDX: 0000200000005100 RSI: 0000200000000000 RDI: 00007f5215955ea0
RBP: 0000200000005100 R08: 00007f5215955ee0 R09: 0000000000000810
R10: 0000000000000810 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f5215955ea0 R14: 000000000000512d R15: 0000200000000080
 </TASK>