rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=73e/1/0x4000000000000004 softirq=411780/411783 fqs=0 
	(t=30008 jiffies g=480877 q=157)
NMI backtrace for cpu 1
CPU: 1 PID: 29532 Comm: kworker/1:0 Not tainted 5.3.0-rc4+ #74
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:1068 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1093
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
RIP: 0010:ffs arch/x86/include/asm/paravirt.h:778 [inline]
RIP: 0010:__do_softirq+0x1ed/0x7c4 kernel/softirq.c:280
Code: 80 3c 38 00 74 0c 48 c7 c7 90 87 8a 88 e8 eb 7b 0c fa 48 83 3d b3 85 ea 00 00 0f 84 dd 05 00 00 0f b7 cb fb 66 0f 1f 44 00 00 <89> 4d 88 b8 ff ff ff ff 0f bc 45 88 41 89 c6 41 ff c6 0f 84 72 01
RSP: 0018:ffff8880aeb09eb8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11150f2 RBX: 0000000004200008 RCX: 0000000000000008
RDX: 0000000080000101 RSI: ffffffff8147c107 RDI: ffffffff87a001bb
RBP: ffff8880aeb09f78 R08: ffffffff817905b4 R09: ffffffff88fbc058
R10: ffffffff88fbc050 R11: ffffffff88fbc043 R12: ffff88809f4825c0
R13: 0000000000000025 R14: 0000000000000000 R15: dffffc0000000000
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x227/0x230 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 do_IRQ+0x171/0x1d0 arch/x86/kernel/irq.c:259
 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:607
 </IRQ>
RIP: 0010:rdtsc_ordered arch/x86/include/asm/msr.h:236 [inline]
RIP: 0010:delay_tsc+0xad/0xf0 arch/x86/lib/delay.c:61
Code: 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 f0 75 d7 f9 e8 ab 79 da fb 41 39 c7 75 bb 0f 01 f9 <66> 90 48 89 d3 48 c1 e3 20 48 09 c3 4c 29 e3 bf 01 00 00 00 e8 2a
RSP: 0018:ffff888062a6fb48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffda
RAX: 00000000c296c7ab RBX: 00000000000020b4 RCX: 0000000000000001
RDX: 00000000000005c2 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff888062a6fb68 R08: ffffffff8353815a R09: fffffbfff11202a4
R10: fffffbfff11202a4 R11: 0000000000000000 R12: 000005c2c296a66d
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