rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7648/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=62249, q=2350 ncpus=2)
task:kworker/0:7     state:R  running task     stack:25416 pid:7648  ppid:2      flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:441
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:seqcount_lockdep_reader_access+0x19a/0x1d0 include/linux/seqlock.h:105
Code: f8 4d 85 e4 75 16 e8 85 e8 bf f8 eb 15 e8 7e e8 bf f8 e8 09 a8 c9 01 4d 85 e4 74 ea e8 6f e8 bf f8 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc9000cd279a0 EFLAGS: 00000293
RAX: ffffffff88c7a2e1 RBX: 0000000000000000 RCX: ffff88802b305a00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000cd27a50 R08: ffffffff911eb597 R09: 1ffffffff223d6b2
R10: dffffc0000000000 R11: fffffbfff223d6b3 R12: 0000000000000200
R13: dffffc0000000000 R14: 1ffff920019a4f34 R15: dffffc0000000000
 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:350 [inline]
 gc_worker+0x314/0x14a0 net/netfilter/nf_conntrack_core.c:1461
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 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>