INFO: task kworker/1:2:1978 blocked for more than 120 seconds. Not tainted 4.17.0-rc1+ #10 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:2 D19800 1978 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:412 Showing all locks held in the system: 2 locks held by khungtaskd/887: #0: 000000008b5a15b1 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 000000008b5a15b1 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000f5f1ec26 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by kworker/1:2/1978: #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000114e1b04 ((wq_completion)"events"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 00000000d4d4982a ((work_completion)(&wb->release_work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 2 locks held by getty/4463: #0: 00000000d56c3398 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000007d4a78c4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4464: #0: 00000000aa7bc1c1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000191af38 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4465: #0: 00000000501ae084 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000009598dc66 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4466: #0: 0000000064b8c988 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d7fb890f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4467: #0: 0000000097ef7feb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000850d7edb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4468: #0: 00000000e9bbe9e2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a5acafbf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4469: #0: 00000000d990ac90 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000044b12ac9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 3 locks held by syz-executor3/5789: #0: 000000002369a4d0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766 #1: 000000003ed8b63f (sb_writers#6){.+.+}, at: file_start_write include/linux/fs.h:2718 [inline] #1: 000000003ed8b63f (sb_writers#6){.+.+}, at: vfs_write+0x452/0x560 fs/read_write.c:548 #2: 0000000078ae22bf (&sb->s_type->i_mutex_key#11){++++}, at: inode_lock include/linux/fs.h:713 [inline] #2: 0000000078ae22bf (&sb->s_type->i_mutex_key#11){++++}, at: generic_file_write_iter+0xe5/0x850 mm/filemap.c:3290 1 lock held by syz-executor5/5793: #0: 00000000d393f10e (&runtime->oss.params_lock){+.+.}, at: snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1503 [inline] #0: 00000000d393f10e (&runtime->oss.params_lock){+.+.}, at: snd_pcm_oss_read+0x3eb/0x800 sound/core/oss/pcm_oss.c:2752 1 lock held by syz-executor4/5801: #0: 00000000199ca463 (event_mutex){+.+.}, at: perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:235 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 887 Comm: khungtaskd Not tainted 4.17.0-rc1+ #10 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:412 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4541 Comm: syz-executor0 Not tainted 4.17.0-rc1+ #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_is_held+0x104/0x140 kernel/locking/lockdep.c:3749 RSP: 0018:ffff8801daf07ad8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8801a5a82bf8 RCX: 0000000000000000 RDX: ffffed003b5e0f40 RSI: ffffffff88d8e460 RDI: ffff8801a5a82c1a RBP: ffff8801daf07b18 R08: ffffed003b5e46c3 R09: ffffed003b5e46c2 R10: ffffed003b5e46c2 R11: ffff8801daf23613 R12: ffff8801a5a823c0 R13: ffffed0034b5057e R14: ffff8801a5a82bf8 R15: 0000000000000001 FS: 0000000001367940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000625208 CR3: 00000001a5a08000 CR4: 00000000001406e0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: lock_is_held_type+0x121/0x210 kernel/locking/lockdep.c:3958 lock_is_held include/linux/lockdep.h:344 [inline] rcu_read_lock_sched_held+0x108/0x120 kernel/rcu/update.c:117 trace_hrtimer_cancel include/trace/events/timer.h:285 [inline] debug_deactivate kernel/time/hrtimer.c:462 [inline] __run_hrtimer kernel/time/hrtimer.c:1356 [inline] __hrtimer_run_queues+0xd57/0x10a0 kernel/time/hrtimer.c:1448 hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1506 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:783 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xa1/0xc0 kernel/locking/spinlock.c:184 RSP: 0018:ffff8801a5a8f1f0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 0000000000000286 RCX: 0000000000000000 RDX: 1ffffffff11a312d RSI: 0000000000000001 RDI: 0000000000000286 RBP: ffff8801a5a8f200 R08: fffffbfff1511206 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8a889028 R13: ffff8801a5a8f250 R14: ffff8801d8d77718 R15: 0000000000000001 debug_object_activate+0x29f/0x670 lib/debugobjects.c:500 debug_rcu_head_queue kernel/rcu/rcu.h:135 [inline] __call_rcu.constprop.68+0xc0/0xbb0 kernel/rcu/tree.c:3018 kfree_call_rcu+0x15/0x20 kernel/rcu/tree.c:3139 sock_destroy_inode+0x47/0x70 net/socket.c:272 destroy_inode+0x151/0x1f0 fs/inode.c:266 evict+0x5cd/0x960 fs/inode.c:574 iput_final fs/inode.c:1519 [inline] iput+0x62d/0xa80 fs/inode.c:1545 dentry_unlink_inode+0x49a/0x620 fs/dcache.c:376 __dentry_kill+0x444/0x770 fs/dcache.c:568 dentry_kill+0xc9/0x5a0 fs/dcache.c:686 dput.part.27+0x648/0x7b0 fs/dcache.c:850 dput+0x1f/0x30 fs/dcache.c:830 __fput+0x552/0x890 fs/file_table.c:227 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x2bd/0x310 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x40f440 RSP: 002b:0000000000a3e328 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000a3e350 RCX: 000000000040f440 RDX: 00000000000000e0 RSI: 0000000000a3e6f0 RDI: 0000000000000013 RBP: 0000000000703360 R08: 0000000000006000 R09: 0000000000004000 R10: 0000000000a3e450 R11: 0000000000000246 R12: 0000000000000013 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000703360 Code: 0f b6 04 02 84 c0 74 04 3c 03 7e 4c 0f b6 43 22 83 e0 03 3b 45 c4 0f 94 c0 48 83 c4 18 5b 0f b6 c0 41 5c 41 5d 41 5e 41 5f 5d c3 <31> c0 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 8b 7d c8