rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3577/1:b..l
	(detected by 1, t=10502 jiffies, g=19913, q=746)
task:kworker/0:4     state:R  running task     stack:23104 pid: 3577 ppid:     2 flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627
Code: 2b 00 74 08 4c 89 f7 e8 bc 73 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90002eb7980 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005d6f3c RCX: 1ffff920005d6edc
RDX: dffffc0000000000 RSI: ffffffff8a8b3cc0 RDI: ffffffff8ad90100
RBP: ffffc90002eb7ae0 R08: dffffc0000000000 R09: fffffbfff20e2219
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005d6f38
R13: dffffc0000000000 R14: ffffc90002eb79e0 R15: 0000000000000246
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 gc_worker+0x289/0x14b0 net/netfilter/nf_conntrack_core.c:1470
 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:287
 </TASK>