rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 ticks this GP) idle=8fe/1/0x4000000000000004 softirq=430481/430481 fqs=0 
	(t=29985 jiffies g=446625 q=183)
rcu: rcu_preempt kthread starved for 29985 jiffies! g446625 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29520    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3254 [inline]
 __schedule+0x755/0x1580 kernel/sched/core.c:3880
 schedule+0xa8/0x270 kernel/sched/core.c:3944
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807
 rcu_gp_fqs_loop kernel/rcu/tree.c:1611 [inline]
 rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1768
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 5748 Comm: kworker/1:3 Not tainted 5.3.0-rc1+ #78
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+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:2736 [inline]
 rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183
 update_process_times+0x32/0x80 kernel/time/timer.c:1639
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1068 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1093
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
RIP: 0010:ffs arch/x86/include/asm/bitops.h:298 [inline]
RIP: 0010:__do_softirq+0x227/0x98c kernel/softirq.c:280
Code: c7 c0 a0 f1 d2 88 48 c1 e8 03 42 80 3c 30 00 0f 85 b1 06 00 00 48 83 3d 86 ef 72 01 00 0f 84 d6 05 00 00 fb 66 0f 1f 44 00 00 <b8> ff ff ff ff 48 c7 45 c8 00 91 c0 88 0f bc 45 d4 83 c0 01 89 45
RSP: 0018:ffff8880ae909f18 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a5e34 RBX: ffff88805a7da6c0 RCX: 1ffffffff134b2be
RDX: 0000000000000000 RSI: ffffffff8178256e RDI: ffffffff876001fc
RBP: ffff8880ae909f98 R08: ffff88805a7da6c0 R09: 0000000000000000
R10: ffffffff89e43050 R11: 0000000000000001 R12: ffff88805b977b08
R13: 0000000000000028 R14: dffffc0000000000 R15: 0000000000000000
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 do_IRQ+0x12c/0x200 arch/x86/kernel/irq.c:259
 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:605
 </IRQ>
RIP: 0010:delay_tsc+0x38/0xc0 arch/x86/lib/delay.c:68
Code: 41 55 41 54 53 e8 58 52 13 fa e8 e3 a6 02 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> 33 52 13 fa e8 be a6 02 fc 44 39 e8 75 36 0f 01 f9 66 90 48 c1
RSP: 0018:ffff88805b977bb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffd7
RAX: 0000000080000000 RBX: 000005291739cf45 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff833e3aac RDI: 0000000000000001
RBP: ffff88805b977bd0 R08: ffff88805a7da6c0 R09: 0000000000000040
R10: 0000000000000040 R11: ffffffff88e53927 R12: 000005291739c3ae
R13: 0000000000000001 R14: 0000000000002ced R15: 0000000000010760
 __delay arch/x86/lib/delay.c:161 [inline]
 __const_udelay+0x59/0x80 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+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352