INFO: rcu_sched detected stalls on CPUs/tasks:
	(detected by 1, t=120002 jiffies, g=14936, c=14935, q=73)
All QSes seen, last rcu_sched kthread activity 120002 (4294878923-4294758921), jiffies_till_next_fqs=3, root ->qsmask 0x0
kworker/u4:2    R  running task    55296    36      2 0x80000008
Workqueue: netns cleanup_net
Call Trace:
 <IRQ>
 sched_show_task+0x600/0x730 kernel/sched/core.c:5279
 print_other_cpu_stall kernel/rcu/tree.c:1480 [inline]
 check_cpu_stall kernel/rcu/tree.c:1598 [inline]
 __rcu_pending kernel/rcu/tree.c:3361 [inline]
 rcu_pending kernel/rcu/tree.c:3423 [inline]
 rcu_check_callbacks+0x292f/0x2cd0 kernel/rcu/tree.c:2763
 update_process_times+0x132/0x1a0 kernel/time/timer.c:1636
 tick_sched_handle kernel/time/tick-sched.c:162 [inline]
 tick_sched_timer+0x33b/0x4b0 kernel/time/tick-sched.c:1194
 __run_hrtimer kernel/time/hrtimer.c:1349 [inline]
 __hrtimer_run_queues+0xc03/0x15d0 kernel/time/hrtimer.c:1411
 hrtimer_interrupt+0x426/0xaf0 kernel/time/hrtimer.c:1469
 local_apic_timer_interrupt+0x66/0x230 arch/x86/kernel/apic/apic.c:1025
 smp_apic_timer_interrupt+0x5a/0x90 arch/x86/kernel/apic/apic.c:1053
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:857
 </IRQ>
RIP: 0010:rep_nop arch/x86/include/asm/processor.h:657 [inline]
RIP: 0010:cpu_relax arch/x86/include/asm/processor.h:662 [inline]
RIP: 0010:csd_lock_wait kernel/smp.c:108 [inline]
RIP: 0010:smp_call_function_single+0x367/0x4f0 kernel/smp.c:302
RSP: 0018:ffff8801d931fa20 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff12
RAX: ffffffff815134f5 RBX: 0000000000000001 RCX: ffff8801d97fd880
RDX: 0000000000000000 RSI: aaaaaaaaaaaab000 RDI: ffffea0000000000
RBP: ffff8801d931faf8 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000180400023 R12: ffff8801d931fa98
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8801d97fe198
 _rcu_barrier+0x497/0x760 kernel/rcu/tree.c:3566
 rcu_barrier_sched kernel/rcu/tree.c:3606 [inline]
 rcu_barrier+0x1c/0x20 kernel/rcu/tree_plugin.h:892
 cleanup_net+0x1309/0x18a0 net/core/net_namespace.c:528
 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2113
 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2247
 kthread+0x539/0x720 kernel/kthread.c:239
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:406
rcu_sched kthread starved for 120002 jiffies! g14936 c14935 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_sched       R  running task    61968     8      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2866 [inline]
 __schedule+0x674/0x730 kernel/sched/core.c:3446
 schedule+0x1cc/0x2f0 kernel/sched/core.c:3505
 schedule_timeout+0x3e7/0x570 kernel/time/timer.c:1801
 rcu_gp_kthread+0x21e1/0x38d0 kernel/rcu/tree.c:2230
 kthread+0x539/0x720 kernel/kthread.c:239
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:406