rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 ticks this GP) idle=832/1/0x4000000000000002 softirq=289395/289395 fqs=0 
	(t=11223 jiffies g=336873 q=329)
rcu: rcu_preempt kthread starved for 11223 jiffies! g336873 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29080    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3254 [inline]
 __schedule+0x877/0xc50 kernel/sched/core.c:3880
 schedule+0x131/0x1e0 kernel/sched/core.c:3947
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1807
 rcu_gp_fqs_loop kernel/rcu/tree.c:1611 [inline]
 rcu_gp_kthread+0xef8/0x1790 kernel/rcu/tree.c:1768
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 18225 Comm: kworker/1:2 Not tainted 5.3.0-rc7+ #0
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+0x1d8/0x2f8 lib/dump_stack.c:113
 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x15a/0x220 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:2736 [inline]
 rcu_sched_clock_irq+0xb95/0x16d0 kernel/rcu/tree.c:2183
 update_process_times+0x134/0x190 kernel/time/timer.c:1639
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1296
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x403/0x850 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1106 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1131
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:preempt_schedule_irq+0xb7/0x140 kernel/sched/core.c:4131
Code: fd f9 43 80 3c 37 00 74 0c 48 c7 c7 90 87 8a 88 e8 5e 50 31 fa 48 83 3d 96 4f 0f 01 00 0f 84 82 00 00 00 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 1f ee ff ff 43 80 3c 34 00 74 0c 48 c7 c7 88 87
RSP: 0018:ffff888094af7a68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff117c400 RBX: 0000000000000000 RCX: ffff88808b342480
RDX: 0000000000000000 RSI: ffffffff87800a20 RDI: ffffffff877b37df
RBP: ffff888094af7a88 R08: ffffffff81790e54 R09: ffffed1015d66a6d
R10: ffffed1015d66a6d R11: 0000000000000000 R12: 1ffffffff11150f1
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffffffff11150f2
 retint_kernel+0x1b/0x2b
RIP: 0010:delay_tsc+0x96/0xf0 arch/x86/lib/delay.c:68
Code: fb 41 89 c7 0f 01 f9 66 90 49 89 d4 49 c1 e4 20 49 09 c4 eb 29 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 a8 01 75 ca f3 90 <bf> 01 00 00 00 e8 20 a4 d6 f9 e8 3b e2 d9 fb 41 39 c7 75 bb 0f 01
RSP: 0018:ffff888094af7b48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff02
RAX: 0000000080000000 RBX: 0000000000000118 RCX: 0000000000000001
RDX: 000000000000042d RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffff888094af7b68 R08: ffffffff8353c06a R09: fffffbfff11202a8
R10: fffffbfff11202a8 R11: 0000000000000000 R12: 0000042dfd70a893
R13: 0000000000000000 R14: 0000000000002ced R15: 0000000000000001
 __delay arch/x86/lib/delay.c:161 [inline]
 __const_udelay+0x5e/0x70 arch/x86/lib/delay.c:175
 try_check_zero+0x6e/0x380 kernel/rcu/srcutree.c:705
 srcu_advance_state kernel/rcu/srcutree.c:1142 [inline]
 process_srcu+0x1b7/0xd20 kernel/rcu/srcutree.c:1237
 process_one_work+0x7ef/0x10e0 kernel/workqueue.c:2269
 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352