INFO: task kworker/u4:0:6 blocked for more than 140 seconds.
Not tainted 4.9.141+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:0 D25352 6 2 0x80000000
Workqueue: netns cleanup_net
ffff8801da678000 ffff8801da7c8580 ffff8801da7c8580 ffff8801cffd0000
ffff8801db721018 ffff8801da687648 ffffffff828075c2 0000000000000286
0000000000000002 0000000041b58ab3 00ffffff82e2b9d2 ffff8801db7218f0
Call Trace:
[<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
[<ffffffff8124aa99>] exp_funnel_lock kernel/rcu/tree_exp.h:279 [inline]
[<ffffffff8124aa99>] _synchronize_rcu_expedited+0x689/0x840 kernel/rcu/tree_exp.h:569
[<ffffffff8124fd62>] synchronize_rcu_expedited+0x22/0x30 kernel/rcu/tree_exp.h:687
[<ffffffff82301f9f>] synchronize_net+0x2f/0x50 net/core/dev.c:7862
[<ffffffff823035f7>] rollback_registered_many+0x7f7/0xb50 net/core/dev.c:6890
[<ffffffff8230d6f8>] unregister_netdevice_many+0x48/0x220 net/core/dev.c:7907
[<ffffffff8279630b>] vti6_destroy_tunnels net/ipv6/ip6_vti.c:1078 [inline]
[<ffffffff8279630b>] vti6_exit_net+0x35b/0x4e0 net/ipv6/ip6_vti.c:1123
[<ffffffff822e3d70>] ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:136
[<ffffffff822e6ad2>] cleanup_net+0x3f2/0x8b0 net/core/net_namespace.c:473
[<ffffffff81131001>] process_one_work+0x831/0x15f0 kernel/workqueue.c:2092
[<ffffffff81131e96>] worker_thread+0xd6/0x1140 kernel/workqueue.c:2226
[<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
[<ffffffff82817a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Showing all locks held in the system:
4 locks held by kworker/u4:0/6:
#0: ("%s""netns"){.+.+.+}, at: [<ffffffff81130f0c>] process_one_work+0x73c/0x15f0 kernel/workqueue.c:2085
#1: (net_cleanup_work){+.+.+.}, at: [<ffffffff81130f44>] process_one_work+0x774/0x15f0 kernel/workqueue.c:2089
#2: (net_mutex){+.+.+.}, at: [<ffffffff822e681f>] cleanup_net+0x13f/0x8b0 net/core/net_namespace.c:439
#3: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
3 locks held by kworker/1:1/22:
#0: ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff81130f0c>] process_one_work+0x73c/0x15f0 kernel/workqueue.c:2085
#1: ((addr_chk_work).work){+.+...}, at: [<ffffffff81130f44>] process_one_work+0x774/0x15f0 kernel/workqueue.c:2089
#2: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
2 locks held by khungtaskd/24:
#0: (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
#0: (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
#1: (tasklist_lock){.+.+..}, at: [<ffffffff813fe63f>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1899:
#0: (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156cc7c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/2026:
#0: (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
#1: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor.2/3024:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.1/3049:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.1/3053:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.3/3052:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.3/3054:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.5/3077:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.5/3078:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor.5/3103:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #1
ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000000
0000000000000000 0000000000000001 ffffffff810983b0 ffff8801d9907d40
ffffffff81b4df89 0000000000000000 0000000000000000 0000000000000002
Call Trace:
[<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
[<ffffffff81b4df89>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
[<ffffffff81b4df1c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
[<ffffffff810984b4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
[<ffffffff8131c65d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
[<ffffffff8131c65d>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff8131c65d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
[<ffffffff8131c65d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
[<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
[<ffffffff82817a5c>] 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 skipped: idling at pc 0xffffffff82816496