INFO: task kworker/u4:4:10912 blocked for more than 140 seconds. Not tainted 4.19.0-rc7+ #283 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:4 D13960 10912 2 0x80000000 Workqueue: events_unbound fsnotify_mark_destroy_workfn Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136 __synchronize_srcu+0x184/0x230 kernel/rcu/srcutree.c:934 synchronize_srcu_expedited kernel/rcu/srcutree.c:959 [inline] synchronize_srcu+0x356/0x5ab kernel/rcu/srcutree.c:1010 fsnotify_mark_destroy_workfn+0x1be/0x510 fs/notify/mark.c:772 process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 INFO: task kworker/0:4:23993 blocked for more than 140 seconds. Not tainted 4.19.0-rc7+ #283 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:4 D22536 23993 2 0x80000000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xbe7/0x1700 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77 addrconf_dad_work+0xb6/0x1310 net/ipv6/addrconf.c:3973 process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 INFO: task syz-executor1:13865 blocked for more than 140 seconds. Not tainted 4.19.0-rc7+ #283 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D22008 13865 5352 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136 _rcu_barrier+0x49d/0x790 kernel/rcu/tree.c:3478 rcu_barrier+0x10/0x20 kernel/rcu/tree_plugin.h:834 netdev_run_todo+0x24d/0xa60 net/core/dev.c:8731 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:117 tun_detach drivers/net/tun.c:750 [inline] tun_chr_close+0xff/0x180 drivers/net/tun.c:3234 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411021 Code: 4c 89 f6 48 89 c7 48 89 ca 48 89 4c 24 10 4c 89 54 24 08 e8 b1 a3 ff ff 48 8b 4c 24 10 41 c6 04 0f 00 4c 8b 7c 24 28 4c 8b 54 <24> 08 45 0f b6 37 e9 db fc ff ff 0f 1f 40 00 41 80 f8 29 74 7f ba RSP: 002b:00007ffdc8281050 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000411021 RDX: 0000000000000000 RSI: 0000000000732b18 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffdc8280f80 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000667 R15: 0000000000000001 Showing all locks held in the system: 1 lock held by khungtaskd/982: #0: 00000000cdfbf2bf (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5209: #0: 00000000c33cafbb (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5299: #0: 00000000a0bf1e1a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000062eda081 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5300: #0: 00000000d30323cc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000070ce1fba (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5301: #0: 00000000c00cc0f6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007d5c79bb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5302: #0: 00000000ba860b79 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006606e0ea (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5303: #0: 00000000d0e52ace (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000baf2d87e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5304: #0: 00000000be435c08 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ef40a4f9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5305: #0: 00000000b3070877 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d87a2547 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by kworker/u4:4/10912: #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000376370c0 ((wq_completion)"events_unbound"){+.+.}, at: process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124 #1: 000000001b72d117 ((reaper_work).work){+.+.}, at: process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128 3 locks held by kworker/0:0/11780: #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000007753238b ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124 #1: 00000000244c3688 (deferred_process_work){+.+.}, at: process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128 #2: 00000000393da39a (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77 3 locks held by kworker/0:4/23993: #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000a43c35d0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124 #1: 0000000091fef22d ((work_completion)(&(&ifa->dad_work)->work)){+.+.}, at: process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128 #2: 00000000393da39a (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77 3 locks held by kworker/1:1/3322: 1 lock held by syz-executor1/13865: #0: 00000000daf50a70 (rcu_preempt_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x144/0x790 kernel/rcu/tree.c:3413 2 locks held by syz-executor0/13867: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 982 Comm: khungtaskd Not tainted 4.19.0-rc7+ #283 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+0x1c4/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb3e/0x1050 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 0 to CPUs 1: INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.342 msecs NMI backtrace for cpu 1 CPU: 1 PID: 13867 Comm: syz-executor0 Not tainted 4.19.0-rc7+ #283 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_read_lock_sched_held+0x88/0x120 kernel/rcu/update.c:119 Code: d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 7d 8b 15 1d 2e 08 08 85 d2 74 09 e8 14 e6 ff ff 85 c0 75 08 b8 01 00 00 00 5b 5d c3 b3 ac 01 00 84 c0 74 4b e8 da ee 00 00 84 c0 74 42 48 b8 00 00 RSP: 0018:ffff8801d7e5e870 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffffff896fe000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff838d2698 RDI: ffff88018f640d3c RBP: ffff8801d7e5e878 R08: ffff88018f6404c0 R09: 1ffffffff1273955 R10: ffffed003b5e4732 R11: ffff8801daf23993 R12: 1ffff1003afcbd1d R13: 1ffff1003afcbd81 R14: 0000000000000000 R15: 1ffff1003afcbd21 FS: 0000000000a65940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002001d000 CR3: 00000001c2f5d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_rcu_utilization include/trace/events/rcu.h:21 [inline] rcu_note_context_switch+0x14b6/0x26b0 kernel/rcu/tree.c:448 __schedule+0x22e/0x1ed0 kernel/sched/core.c:3401 schedule+0xfe/0x460 kernel/sched/core.c:3517 do_sched_yield+0x1bf/0x2a0 kernel/sched/core.c:4950 yield+0xb3/0xe0 kernel/sched/core.c:5025 dev_deactivate_many+0x5d3/0xdd0 net/sched/sch_generic.c:1187 __dev_close_many+0x197/0x380 net/core/dev.c:1461 dev_close_many+0x2df/0x860 net/core/dev.c:1499 rollback_registered_many+0x543/0x1210 net/core/dev.c:7953 rollback_registered+0x1e9/0x420 net/core/dev.c:8018 unregister_netdevice_queue+0x321/0x5e0 net/core/dev.c:9062 unregister_netdevice include/linux/netdevice.h:2599 [inline] __tun_detach+0x11b8/0x15c0 drivers/net/tun.c:730 tun_detach drivers/net/tun.c:747 [inline] tun_chr_close+0xe3/0x180 drivers/net/tun.c:3234 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411021 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fff3954d220 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 000000000000000f RCX: 0000000000411021 RDX: 0000000000000000 RSI: 0000000000732b80 RDI: 000000000000000e RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00007fff3954d150 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00000000000005c6 R15: 0000000000000000