serio: Serial port pts2
BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 166s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
  pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=10/256
    in-flight: 5256:rtc_timer_do_work
    pending: vmstat_shepherd, dst_gc_task, destroy_super_work, destroy_super_work, destroy_super_work, destroy_super_work, key_garbage_collector, wait_rcu_exp_gp, proc_cleanup_work
workqueue events_long: flags=0x0
  pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256
    pending: serio_handle_event
workqueue events_power_efficient: flags=0x80
  pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256
    pending: ioc_release_fn, check_lifetime
workqueue netns: flags=0xe000a
  pwq 4: cpus=0-1 flags=0x4 nice=0 active=1/1
    in-flight: 9074:cleanup_net
    delayed: cleanup_net
workqueue vmstat: flags=0xc
  pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256
    pending: vmstat_update
workqueue ipv6_addrconf: flags=0x40008
  pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/1
    pending: addrconf_verify_work
pool 2: cpus=1 node=0 flags=0x0 nice=0 hung=167s workers=4 idle: 5258 18 22
pool 4: cpus=0-1 flags=0x4 nice=0 hung=1s workers=12 idle: 2260 9080 64 2221 2281 2438 9096 9091 3160 9071 6
INFO: task kworker/u4:8:9074 blocked for more than 140 seconds.
      Not tainted 4.9.133+ #52
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:8    D28696  9074      2 0x80000000
Workqueue: netns cleanup_net
 ffff88019e2edf00 0000000000000000 ffff88019eb2d800 ffff8801d84b17c0
 ffff8801db721018 ffff88019da17528 ffffffff827f3792 0000000000000004
 ffff88019e2ee7b0 ffffed0033c5dcf5 00ff88019e2edf00 ffff8801db7218f0
Call Trace:
 [<ffffffff827f4cbf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff827f5643>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff827f76bd>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff827f76bd>] mutex_lock_nested+0x38d/0x900 kernel/locking/mutex.c:621
 [<ffffffff8124a1a7>] exp_funnel_lock kernel/rcu/tree_exp.h:289 [inline]
 [<ffffffff8124a1a7>] _synchronize_rcu_expedited+0x3a7/0x840 kernel/rcu/tree_exp.h:569
 [<ffffffff8124f752>] synchronize_rcu_expedited+0x22/0x30 kernel/rcu/tree_exp.h:687
 [<ffffffff822ef88f>] synchronize_net+0x2f/0x50 net/core/dev.c:7834
 [<ffffffff822f0cb4>] rollback_registered_many+0x5c4/0xb50 net/core/dev.c:6820
 [<ffffffff822fafe8>] unregister_netdevice_many+0x48/0x220 net/core/dev.c:7879
 [<ffffffff8279aebd>] ip6_tnl_destroy_tunnels net/ipv6/ip6_tunnel.c:2183 [inline]
 [<ffffffff8279aebd>] ip6_tnl_exit_net+0x3dd/0x5b0 net/ipv6/ip6_tunnel.c:2230
 [<ffffffff822d1770>] ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:136
 [<ffffffff822d44d2>] cleanup_net+0x3f2/0x8b0 net/core/net_namespace.c:473
 [<ffffffff81130d61>] process_one_work+0x831/0x1530 kernel/workqueue.c:2092
 [<ffffffff81131b36>] worker_thread+0xd6/0x1140 kernel/workqueue.c:2226
 [<ffffffff811428dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82803bdc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131baec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131baec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.?..}, at: [<ffffffff813fe2b4>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2037:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82801ae2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d2b472>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor2/7693:
 #0:  (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<ffffffff8228988b>] inode_lock include/linux/fs.h:766 [inline]
 #0:  (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<ffffffff8228988b>] __sock_release+0x8b/0x260 net/socket.c:604
5 locks held by kworker/u4:8/9074:
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff81130c6c>] process_one_work+0x73c/0x1530 kernel/workqueue.c:2085
 #1:  (net_cleanup_work){+.+.+.}, at: [<ffffffff81130ca4>] process_one_work+0x774/0x1530 kernel/workqueue.c:2089
 #2:  (net_mutex){+.+.+.}, at: [<ffffffff822d421f>] cleanup_net+0x13f/0x8b0 net/core/net_namespace.c:439
 #3:  (rtnl_mutex){+.+.+.}, at: [<ffffffff8232eb57>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #4:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a1a7>] exp_funnel_lock kernel/rcu/tree_exp.h:289 [inline]
 #4:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a1a7>] _synchronize_rcu_expedited+0x3a7/0x840 kernel/rcu/tree_exp.h:569
2 locks held by syz-executor2/11274:
 #0:  (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<ffffffff8228988b>] inode_lock include/linux/fs.h:766 [inline]
 #0:  (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<ffffffff8228988b>] __sock_release+0x8b/0x260 net/socket.c:604
 #1:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a139>] exp_funnel_lock kernel/rcu/tree_exp.h:256 [inline]
 #1:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a139>] _synchronize_rcu_expedited+0x339/0x840 kernel/rcu/tree_exp.h:569

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.133+ #52
 ffff8801d9907d08 ffffffff81b37069 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff81098330 ffff8801d9907d40
 ffffffff81b42179 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b37069>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b37069>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b42179>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4210c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff81098434>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c07d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c07d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c07d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c07d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff811428dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82803bdc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5256 Comm: kworker/1:2 Not tainted 4.9.133+ #52
Workqueue: events rtc_timer_do_work
c
task: ffff88019eb04740 task.stack: ffff88019e5c0000
RIP: 0010:[<ffffffff8120c960>] 
c [<ffffffff8120c960>] __lock_release kernel/locking/lockdep.c:3516 [inline]
RIP: 0010:[<ffffffff8120c960>] 
c [<ffffffff8120c960>] lock_release+0x130/0xc20 kernel/locking/lockdep.c:3775
RSP: 0018:ffff88019e5c7958  EFLAGS: 00000002
RAX: ffff88019eb04740 RBX: ffff8801d60ffc50 RCX: 1ffff1003ac1ff86
RDX: 0000000000000004 RSI: 0000000000000001 RDI: ffffffff831f2a20
RBP: ffff88019e5c7a00 R08: ffff88019eb05088 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: ffff8801d60ffc38
R13: ffff88019eb04740 R14: ffff8801d60ffc38 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000016f1308 CR3: 00000001d2f30000 CR4: 00000000001606b0
Stack:
 0000000000000046
c ffff88019eb04740
c 0000000000000000
c 0000000000000000
c
 0000000000000000
c ffff88019e5c79f8
c 0000000000000046
c 0000000000000000
c
 ffffffff8207ce8e
c ffffffff00000000
c 0000000000000000
c 0000000000000046
c
Call Trace:
 [<ffffffff8280310f>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
 [<ffffffff8280310f>] _raw_spin_unlock_irqrestore+0x1f/0x70 kernel/locking/spinlock.c:191
 [<ffffffff8207cee1>] spin_unlock_irqrestore include/linux/spinlock.h:362 [inline]
 [<ffffffff8207cee1>] rtc_handle_legacy_irq+0x81/0x190 drivers/rtc/interface.c:515
 [<ffffffff8207d03f>] rtc_uie_update_irq+0x1f/0x30 drivers/rtc/interface.c:550
 [<ffffffff8207d32f>] rtc_timer_do_work+0x1ff/0x5e0 drivers/rtc/interface.c:881
 [<ffffffff81130d61>] process_one_work+0x831/0x1530 kernel/workqueue.c:2092
 [<ffffffff81131b36>] worker_thread+0xd6/0x1140 kernel/workqueue.c:2226
 [<ffffffff811428dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82803bdc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
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