rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P27/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=73609, q=728 ncpus=2)
task:kworker/1:1     state:R  running task     stack:22536 pid:27    ppid:2      flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:seqcount_lockdep_reader_access+0x17f/0x1c0 include/linux/seqlock.h:105
Code: f8 4d 85 e4 75 16 e8 10 1c d9 f8 eb 15 e8 09 1c d9 f8 e8 14 a9 c2 01 4d 85 e4 74 ea e8 fa 1b d9 f8 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00
RSP: 0018:ffffc90000a2f9a0 EFLAGS: 00000293
RAX: ffffffff88ac74c6 RBX: 0000000000000000 RCX: ffff88801ca4bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000a2fa50 R08: ffffffff90da9597 R09: 1ffffffff21b52b2
R10: dffffc0000000000 R11: fffffbfff21b52b3 R12: 0000000000000200
R13: dffffc0000000000 R14: 1ffff92000145f34 R15: dffffc0000000000
 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:350 [inline]
 gc_worker+0x317/0x14b0 net/netfilter/nf_conntrack_core.c:1504
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>