rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 ticks this GP) idle=f92/1/0x4000000000000002 softirq=400968/400968 fqs=0 
	(t=11204 jiffies g=522125 q=298)
rcu: rcu_preempt kthread starved for 11204 jiffies! g522125 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I26176    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:2818 [inline]
 __schedule+0x658/0x9e0 kernel/sched/core.c:3445
 schedule+0x131/0x1d0 kernel/sched/core.c:3509
 schedule_timeout+0x19d/0x2b0 kernel/time/timer.c:1807
 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline]
 rcu_gp_kthread+0xfd8/0x1880 kernel/rcu/tree.c:1746
 kthread+0x325/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 25670 Comm: kworker/1:2 Not tainted 5.2.0-rc6+ #8
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+0x89/0x160 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x125/0x230 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:2625 [inline]
 rcu_sched_clock_irq+0xc10/0x1740 kernel/rcu/tree.c:2161
 update_process_times+0x134/0x190 kernel/time/timer.c:1639
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x257/0x410 kernel/time/tick-sched.c:1298
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x471/0x8b0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 smp_apic_timer_interrupt+0xee/0x260 arch/x86/kernel/apic/apic.c:1066
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:check_preemption_disabled+0x1c/0x280 lib/smp_processor_id.c:14
Code: c6 c0 f2 76 88 e8 04 00 00 00 5d c3 66 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 10 49 89 f6 49 89 ff e8 04 fb 14 fe <65> 44 8b 2d 2c da a0 7c 65 8b 1d 51 46 a1 7c 89 de 81 e6 ff ff ff
RSP: 0018:ffff888057d5fa88 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffffffff8360b6ec RBX: 00000000000012a4 RCX: ffff888060346300
RDX: 0000000000000000 RSI: ffffffff8876f2c0 RDI: ffffffff885cb4e8
RBP: ffff888057d5fac0 R08: ffffffff8360b70a R09: fffffbfff115fb26
R10: fffffbfff115fb26 R11: 1ffffffff115fb25 R12: 0000061a8e6e946d
R13: 0000000000000000 R14: ffffffff8876f2c0 R15: ffffffff885cb4e8
 debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:57
 delay_tsc+0xa5/0xf0 arch/x86/lib/delay.c:79
 __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+0x814/0x1130 kernel/workqueue.c:2269
 worker_thread+0xc01/0x1640 kernel/workqueue.c:2415
 kthread+0x325/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352