rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3655/1:b..l
	(detected by 1, t=10502 jiffies, g=14321, q=92 ncpus=2)
task:kworker/u4:5    state:R  running task     stack:24320 pid:3655  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:inet_twsk_purge+0x716/0xb60 net/ipv4/inet_timewait_sock.c:337
Code: 38 c1 0f 8c dd fe ff ff 48 8d bc 24 a0 00 00 00 e8 5f 9d d9 f8 e9 cb fe ff ff e8 35 3f 82 f8 49 d1 ed 4c 89 ef 48 8b 5c 24 58 <48> 89 de e8 02 41 82 f8 49 39 dd 0f 84 fe 02 00 00 e8 14 3f 82 f8
RSP: 0018:ffffc9000474fa60 EFLAGS: 00000203
RAX: ffffffff890855cb RBX: 000000000002e015 RCX: ffff88807b823b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000002e015
RBP: ffffc9000474fb70 R08: ffffffff890850c9 R09: fffffbfff2092045
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 000000000002e015 R14: ffffffff920e2000 R15: ffff888028d700a8
 ops_exit_list net/core/net_namespace.c:174 [inline]
 cleanup_net+0x763/0xb60 net/core/net_namespace.c:601
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10411 jiffies! g14321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=8647
rcu: rcu_preempt kthread starved for 10412 jiffies! g14321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:26648 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
 rcu_gp_fqs_loop+0x2d2/0x1120 kernel/rcu/tree.c:1674
 rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1873
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:572