rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3711/1:b..l
	(detected by 0, t=10502 jiffies, g=28337, q=327)
task:kworker/u4:7    state:R  running task     stack:19928 pid: 3711 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6552
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6577
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __local_bh_enable_ip+0x175/0x1f0 kernel/softirq.c:390
 spin_unlock_bh include/linux/spinlock.h:408 [inline]
 sctp_inet6addr_event+0x64e/0x700 net/sctp/ipv6.c:113
 notifier_call_chain kernel/notifier.c:83 [inline]
 atomic_notifier_call_chain+0x15f/0x290 kernel/notifier.c:198
 addrconf_ifdown+0xecd/0x1bb0 net/ipv6/addrconf.c:3902
 addrconf_notify+0x432/0xf30
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2018 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
 call_netdevice_notifiers net/core/dev.c:2044 [inline]
 dev_close_many+0x37c/0x530 net/core/dev.c:1619
 unregister_netdevice_many+0x4b0/0x18f0 net/core/dev.c:11069
 default_device_exit_batch+0x390/0x3f0 net/core/dev.c:11626
 ops_exit_list net/core/net_namespace.c:174 [inline]
 cleanup_net+0x763/0xb60 net/core/net_namespace.c:596
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
rcu: rcu_preempt kthread starved for 9818 jiffies! g28337 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:R  running task     stack:27000 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:570