rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P23/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=174033, q=1689 ncpus=2)
task:kworker/1:0     state:R  running task     stack:21720 pid:23    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:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
RIP: 0010:rcu_is_watching+0x8/0xb0 kernel/rcu/tree.c:699
Code: ee f7 1f 09 48 c7 c7 40 89 13 8d 4c 89 f6 e8 ff 24 f6 02 e9 44 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 57 41 56 <53> 65 ff 05 e8 65 92 7e e8 ab 0d 20 09 89 c3 83 f8 08 73 60 49 bf
RSP: 0018:ffffc900001d7a48 EFLAGS: 00000202
RAX: ffffffff88c8483e RBX: 000000000000188d RCX: 0000000000000000
RDX: ffff88801ca55a00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001d7bb0 R08: ffffffff911eb597 R09: 1ffffffff223d6b2
R10: dffffc0000000000 R11: fffffbfff223d6b3 R12: 000000000000311b
R13: dffffc0000000000 R14: 0000000000000001 R15: 000000000000188d
 rcu_read_unlock include/linux/rcupdate.h:815 [inline]
 gc_worker+0xcb8/0x14a0 net/netfilter/nf_conntrack_core.c:1536
 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>