INFO: task kworker/1:0:18 blocked for more than 120 seconds. Not tainted 4.16.0+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:0 D19800 18 2 0x80000000 Workqueue: events cgwb_release_workfn Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 bit_wait+0x18/0x90 kernel/sched/wait_bit.c:197 __wait_on_bit+0xb3/0x130 kernel/sched/wait_bit.c:48 out_of_line_wait_on_bit+0x204/0x3a0 kernel/sched/wait_bit.c:63 wait_on_bit include/linux/wait_bit.h:76 [inline] wb_shutdown+0x370/0x470 mm/backing-dev.c:366 cgwb_release_workfn+0x87/0x750 mm/backing-dev.c:509 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Showing all locks held in the system: 2 locks held by kworker/1:0/18: #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 0000000021da0506 ((wq_completion)"events"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 00000000a31111cc ((work_completion)(&wb->release_work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 2 locks held by khungtaskd/888: #0: 00000000b0e8b7e5 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000b0e8b7e5 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000058730d7 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by getty/4462: #0: 000000003bfcecc4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000065cfcac9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4463: #0: 00000000727535f5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ee04f0ea (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4464: #0: 00000000f9a886b5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000874aea8b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4465: #0: 0000000054485be3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003332c04b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4466: #0: 000000005215b172 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c59e8d42 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4467: #0: 000000004874b33e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000005517931 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4468: #0: 00000000a143be14 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000005fe74fce (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 3 locks held by syz-executor0/23428: #0: 00000000456b128c (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766 #1: 000000000f67f115 (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2718 [inline] #1: 000000000f67f115 (sb_writers#4){.+.+}, at: vfs_write+0x452/0x560 fs/read_write.c:548 #2: 00000000bb155aa3 (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:733 [inline] #2: 00000000bb155aa3 (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x242/0x12e0 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 888 Comm: khungtaskd Not tainted 4.16.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 23432 Comm: syz-executor4 Not tainted 4.16.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_is_held+0x9e/0x140 kernel/locking/lockdep.c:3737 RSP: 0018:ffff8801953ee6d8 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff8801c890eca0 RCX: 0000000000000001 RDX: ffffed0032a7dcc0 RSI: ffff8801db02c598 RDI: ffff8801c890ecc2 RBP: ffff8801953ee718 R08: ffff8801c7b14300 R09: ffff8801c890e618 R10: ffffed003b6058b0 R11: ffff8801db02c583 R12: ffff8801c890e440 R13: ffffed0039121d8e R14: ffff8801c890ec78 R15: 0000000000000002 FS: 00000000012ef940(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8499933000 CR3: 0000000199c26000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held_type+0x121/0x210 kernel/locking/lockdep.c:3958 lock_is_held include/linux/lockdep.h:344 [inline] rq_clock_task kernel/sched/sched.h:973 [inline] update_curr+0x332/0xbe0 kernel/sched/fair.c:807 put_prev_entity+0xad/0x2a0 kernel/sched/fair.c:4447 pick_next_task_fair+0xec0/0x1660 kernel/sched/fair.c:6989 pick_next_task kernel/sched/core.c:3336 [inline] __schedule+0x491/0x1e30 kernel/sched/core.c:3464 preempt_schedule_common+0x22/0x60 kernel/sched/core.c:3629 _cond_resched+0x1d/0x30 kernel/sched/core.c:4978 __mutex_lock_common kernel/locking/mutex.c:747 [inline] __mutex_lock+0x142/0x17f0 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 arch_jump_label_transform+0x1b/0x40 arch/x86/kernel/jump_label.c:109 __jump_label_update+0x16e/0x1a0 kernel/jump_label.c:375 jump_label_update+0x151/0x2e0 kernel/jump_label.c:760 __static_key_slow_dec_cpuslocked+0xb0/0x200 kernel/jump_label.c:205 __static_key_slow_dec kernel/jump_label.c:215 [inline] static_key_slow_dec+0x63/0xa0 kernel/jump_label.c:229 preempt_notifier_dec+0x10/0x20 kernel/sched/core.c:2475 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:736 [inline] kvm_put_kvm+0xa82/0x1040 arch/x86/kvm/../../../virt/kvm/kvm_main.c:750 kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:761 __fput+0x34d/0x890 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1aee/0x2730 kernel/exit.c:865 do_group_exit+0x16f/0x430 kernel/exit.c:968 SYSC_exit_group kernel/exit.c:979 [inline] SyS_exit_group+0x1d/0x20 kernel/exit.c:977 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x455319 RSP: 002b:00007ffc445220f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000290 RCX: 0000000000455319 RDX: 0000000000000251 RSI: 0000000000732590 RDI: 0000000000000000 RBP: 00000000ffffffff R08: 00000000000010c6 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000013 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000001380 Code: 08 00 00 85 c0 7f 24 e9 85 00 00 00 41 0f b6 45 00 41 83 c7 01 84 c0 74 08 3c 03 0f 8e 8f 00 00 00 45 39 bc 24 30 08 00 00 7e 66 <49> 63 c7 48 8b 75 d0 48 8d 04 80 49 8d 1c c6 48 89 df e8 db f4