rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6619/1:b..l
	(detected by 1, t=10502 jiffies, g=32969, q=1580)
task:kworker/1:12    state:R  running task     stack:24840 pid: 6619 ppid:     2 flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:1119 [inline]
RIP: 0010:rcu_is_watching+0x4/0xa0 kernel/rcu/tree.c:1122
Code: 8d 65 e8 5b 41 5e 41 5f 5d c3 e8 87 94 3d 08 41 f7 c7 00 02 00 00 75 b8 eb b7 e8 67 94 3d 08 0f 1f 80 00 00 00 00 41 57 41 56 <53> 65 ff 05 1c d7 9e 7e e8 5f a4 3d 08 89 c3 83 f8 08 73 5c 49 bf
RSP: 0018:ffffc900033afac8 EFLAGS: 00000202
RAX: ffffffff880f0a69 RBX: 0000000000000001 RCX: ffff888079125940
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900033afc30 R08: dffffc0000000000 R09: fffffbfff1ff322c
R10: fffffbfff1ff322c R11: 1ffffffff1ff322b R12: dffffc0000000000
R13: ffff88801e795e00 R14: 00000000000732a7 R15: 0000000000040000
 rcu_read_unlock include/linux/rcupdate.h:768 [inline]
 gc_worker+0xbe2/0x13a0 net/netfilter/nf_conntrack_core.c:1543
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>