rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5874/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=50361, q=444674 ncpus=2)
task:kworker/0:3     state:R  running task     stack:14984 pid:5874  tgid:5874  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_power_efficient gc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1585/0x5340 kernel/sched/core.c:6907
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
 irqentry_exit+0x599/0x620 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:seqcount_lockdep_reader_access+0xed/0x100 include/linux/seqlock.h:76
Code: 00 75 11 e8 e5 9c ef f7 4d 85 f6 75 16 e8 db 9c ef f7 eb 15 e8 d4 9c ef f7 e8 0f 8c e4 01 4d 85 f6 74 ea e8 c5 9c ef f7 fb 5b <41> 5e e9 8c 72 e7 01 cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc900041179d0 EFLAGS: 00000293
RAX: ffffffff89d6568b RBX: 0000000000000001 RCX: ffff88807ff7bc80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004117b30 R08: ffffffff9033cab7 R09: 1ffffffff2067956
R10: dffffc0000000000 R11: fffffbfff2067957 R12: dffffc0000000000
R13: 1ffff1100ffef820 R14: 0000000000000200 R15: 0000000000000fac
 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:343 [inline]
 gc_worker+0x304/0x1290 net/netfilter/nf_conntrack_core.c:1548
 process_one_work+0x949/0x1650 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>