rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 ticks this GP) idle=326/1/0x4000000000000002 softirq=191886/191886 fqs=0 
	(t=29997 jiffies g=305737 q=2410)
rcu: rcu_preempt kthread starved for 29997 jiffies! g305737 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29056    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:2817 [inline]
 __schedule+0x7d1/0x1580 kernel/sched/core.c:3444
 schedule+0xa8/0x260 kernel/sched/core.c:3508
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807
 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline]
 rcu_gp_kthread+0x9a3/0x1830 kernel/rcu/tree.c:1746
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 14558 Comm: kworker/1:5 Not tainted 5.1.0+ #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp process_srcu
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2625 [inline]
 rcu_sched_clock_irq.cold+0x4d1/0xbfd kernel/rcu/tree.c:2161
 update_process_times+0x32/0x80 kernel/time/timer.c:1639
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1298
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1040 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1065
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:preempt_count_add+0x0/0x1b0 kernel/sched/core.c:3171
Code: f5 48 c7 c2 60 cf 6a 87 be 54 02 00 00 48 c7 c7 e0 c5 6a 87 c6 05 5b 05 0e 08 01 e8 b5 05 0a 00 c9 c3 0f 1f 84 00 00 00 00 00 <48> b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 54 41 89 fc 53 48 c7
RSP: 0018:ffff888092ea7ba8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 0000000080000000 RBX: 000005377ba747a6 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff8334662c RDI: 0000000000000001
RBP: ffff888092ea7bd0 R08: ffff8880a0c4e080 R09: 0000000000000040
R10: 0000000000000040 R11: ffffffff88a42a67 R12: 000005377ba72c70
R13: 0000000000000001 R14: 0000000000002ced R15: 0000000000000abd
 __delay arch/x86/lib/delay.c:161 [inline]
 __const_udelay+0x5f/0x80 arch/x86/lib/delay.c:175
 try_check_zero+0x201/0x330 kernel/rcu/srcutree.c:705
 srcu_advance_state kernel/rcu/srcutree.c:1142 [inline]
 process_srcu+0x329/0xe20 kernel/rcu/srcutree.c:1237
 process_one_work+0x98e/0x1790 kernel/workqueue.c:2263
 worker_thread+0x98/0xe40 kernel/workqueue.c:2409
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352