rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=872/1/0x4000000000000002 softirq=83610/83611 fqs=0 
rcu: 	 (t=11063 jiffies g=100525 q=204)
rcu: rcu_preempt kthread starved for 11063 jiffies! g100525 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29496    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2877 [inline]
 __schedule+0x817/0x1cc0 kernel/sched/core.c:3518
 schedule+0x92/0x180 kernel/sched/core.c:3562
 schedule_timeout+0x4db/0xfd0 kernel/time/timer.c:1803
 rcu_gp_fqs_loop kernel/rcu/tree.c:1971 [inline]
 rcu_gp_kthread+0x962/0x17b0 kernel/rcu/tree.c:2128
 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: 7849 Comm: kworker/1:3 Not tainted 5.1.0-rc4+ #61
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.c:1223
 print_cpu_stall kernel/rcu/tree.c:1360 [inline]
 check_cpu_stall kernel/rcu/tree.c:1434 [inline]
 rcu_pending kernel/rcu/tree.c:3103 [inline]
 rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __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:1035 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:preempt_schedule_irq+0xab/0x140 kernel/sched/core.c:3745
Code: 00 00 e8 c8 5e 3e fa e8 a3 63 66 fa 4c 89 f0 48 c1 e8 03 80 3c 18 00 75 6c 48 83 3d 5e ff 82 01 00 74 5e fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 cb d5 ff ff 48 c7 c0 78 96 92 88 48 c1 e8 03 80
RSP: 0018:ffff88808fbbfad8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11252d0 RBX: dffffc0000000000 RCX: 1ffff11010d4e5ce
RDX: 0000000000000000 RSI: ffff888086a72e50 RDI: ffff888086a72dfc
RBP: ffff88808fbbfaf8 R08: ffff888086a72580 R09: ffff888086a72e70
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1010d4e4b0
R13: ffff888086a72580 R14: ffffffff88929680 R15: 0000000000000000
 retint_kernel+0x1b/0x2d
RIP: 0010:delay_tsc+0x33/0xc0 arch/x86/lib/delay.c:68
Code: bf 01 00 00 00 41 55 41 54 53 e8 78 b6 3f fa e8 43 59 23 fc 41 89 c5 0f 01 f9 66 90 48 c1 e2 20 48 09 c2 49 89 d4 eb 16 f3 90 <bf> 01 00 00 00 e8 53 b6 3f fa e8 1e 59 23 fc 44 39 e8 75 36 0f 01
RSP: 0018:ffff88808fbbfbb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02
RAX: 0000000080000000 RBX: 0000018af9c23435 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff833198dc RDI: 0000000000000001
RBP: ffff88808fbbfbd0 R08: ffff888086a72580 R09: 0000000000000040
R10: 0000000000000040 R11: ffffc900138c7b87 R12: 0000018af9c22790
R13: 0000000000000001 R14: 0000000000002ced R15: 0000000000000001
 __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:709
 srcu_advance_state kernel/rcu/srcutree.c:1146 [inline]
 process_srcu+0x329/0xe20 kernel/rcu/srcutree.c:1241
 process_one_work+0x98e/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352