INFO: task kworker/u8:2:42 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:20384 pid:42    tgid:42    ppid:2      task_flags:0x4208160 flags:0x00080000
Workqueue: writeback wb_w[ 1246.611998][   T37] Workqueue: writeback wb_workfn (flush-7:7)
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]
 schedule+0x164/0x360 kernel/sched/core.c:7005
 io_schedule+0x80/0xe0 kernel/sched/core.c:7832
 TXN_SLEEP_DROP_LOCK fs/jfs/jfs_txnmgr.c:125 [inline]
 txBegin+0x27d/0xc00 fs/jfs/jfs_txnmgr.c:375
 jfs_commit_inode+0x1b3/0x530 fs/jfs/inode.c:107
 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
 write_inode fs/fs-writeback.c:1582 [inline]
 __writeback_single_inode+0x75d/0x11a0 fs/fs-writeback.c:1813
 writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2042
 wb_writeback+0x456/0xb70 fs/fs-writeback.c:2227
 wb_do_writeback fs/fs-writeback.c:2374 [inline]
 wb_workfn+0x41a/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:436
 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>
INFO: task syz-executor:18319 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22400 pid:18319 tgid:18319 ppid:1      task_flags:0x400140 flags:0x00080002
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]
 schedule+0x164/0x360 kernel/sched/core.c:7005
 wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
 __writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2838
 sync_filesystem+0xa2/0x250 fs/sync.c:54
 generic_shutdown_super+0x77/0x2d0 fs/super.c:625
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 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: 0033:0x7fc2c663d9d7
RSP: 002b:00007ffe627f5ea8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc2c66d1f90 RCX: 00007fc2c663d9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe627f5f60
RBP: 00007ffe627f5f60 R08: 00007ffe627f6f60 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe627f6ff0
R13: 00007fc2c66d1f90 R14: 0000000000109a9b R15: 00007ffe627f7030
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
 #0: ffff888019c17310 (&vn->busy.lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #0: ffff888019c17310 (&vn->busy.lock){+.+.}-{3:3}, at: alloc_vmap_area+0xcb4/0x14b0 mm/vmalloc.c:2121
1 lock held by khungtaskd/37:
 #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
2 locks held by kworker/u8:2/42:
 #0: ffff88801ee9f138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff88801ee9f138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc90000b47c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc90000b47c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
3 locks held by kworker/u8:3/56:
 #0: ffff88803202c138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff88803202c138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc9000122fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc9000122fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
 #2: ffffffff8f15bf38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8f15bf38 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4198
3 locks held by kworker/u8:11/1432:
 #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: ffffc900062d7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc900062d7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
 #2: ffffffff8f15bf38 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by getty/5552:
 #0: ffff8880328fe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:4/5807:
 #0: ffff888019c03938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c03938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc9000474fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc9000474fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
 #2: ffff888057d2f260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
1 lock held by udevd/5820:
1 lock held by udevd/9515:
 #0: ffff888022755528 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff888022755528 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:854
1 lock held by syz-executor/18319:
 #0: ffff888037a100d0 (&type->s_umount_key#67){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888037a100d0 (&type->s_umount_key#67){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888037a100d0 (&type->s_umount_key#67){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
4 locks held by syz-executor/19291:
1 lock held by syz.6.1781/20472:
 #0: ffff888037a100d0 (&type->s_umount_key#67){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
 #0: ffff888037a100d0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
1 lock held by syz-executor/20794:
 #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline]
 #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xe1/0x740 kernel/exit.c:1678
1 lock held by syz-executor/21384:
1 lock held by dhcpcd-run-hook/21510:
 #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline]
 #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xe1/0x740 kernel/exit.c:1678
2 locks held by syz.9.1914/21561:
 #0: ffff888061ed40d0 (&type->s_umount_key#101/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
 #1: ffffffff8dc6d978 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5278 [inline]
 #1: ffffffff8dc6d978 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9ef/0x1e90 kernel/workqueue.c:5831
4 locks held by rm/21571:
3 locks held by syz.5.1916/21577:
1 lock held by syz.1.1917/21574:
 #0: ffff888019c17310 (&vn->busy.lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #0: ffff888019c17310 (&vn->busy.lock){+.+.}-{3:3}, at: alloc_vmap_area+0xcb4/0x14b0 mm/vmalloc.c:2121
3 locks held by syz.1.1917/21576:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 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:436
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 19291 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:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319
Code: 48 8d 3d e3 10 4b 04 48 c7 c6 5d 74 54 8d 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 31 c0 83 3d a3 e8 47 04 00 74 1d 83 3d ba fa 47 04 00
RSP: 0018:ffffc900041bf778 EFLAGS: 00000292
RAX: 1ed9e8bf04b93300 RBX: 1ffff92000837ef4 RCX: 0000000000000046
RDX: 0000000013fa836b RSI: ffffffff8d7ba6f2 RDI: ffffffff8ba64e00
RBP: ffffc900041bf830 R08: ffffffff8b24b1d0 R09: ffffffff8ddcd780
R10: dffffc0000000000 R11: fffffbfff1ed49f7 R12: ffff88802e181e80
R13: dffffc0000000000 R14: ffff8880548bd0a0 R15: ffffc900041bf7c0
FS:  0000555568799500(0000) GS:ffff88812643d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffaaec34000 CR3: 00000000376b8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rcu_read_lock include/linux/rcupdate.h:851 [inline]
 __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 rt_spin_lock+0x205/0x400 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 f2fs_sync_inode_meta fs/f2fs/checkpoint.c:1349 [inline]
 block_operations fs/f2fs/checkpoint.c:1470 [inline]
 f2fs_write_checkpoint+0xb3b/0x26a0 fs/f2fs/checkpoint.c:1885
 kill_f2fs_super+0x314/0x720 fs/f2fs/super.c:5493
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 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: 0033:0x7f558f05d9d7
Code: a2 c7 05 1c ed 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffdbd530988 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f558f0f1f90 RCX: 00007f558f05d9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdbd530a40
RBP: 00007ffdbd530a40 R08: 00007ffdbd531a40 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdbd531ad0
R13: 00007f558f0f1f90 R14: 000000000012858c R15: 00007ffdbd531b10
 </TASK>