rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 ticks this GP) idle=182/1/0x4000000000000002 softirq=53114/53114 fqs=0 
	(t=10986 jiffies g=85749 q=190)
rcu: rcu_preempt kthread starved for 10986 jiffies! g85749 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29040    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3265 [inline]
 __schedule+0x76e/0x17d0 kernel/sched/core.c:3937
 schedule+0xa8/0x270 kernel/sched/core.c:4001
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1893
 rcu_gp_fqs_loop kernel/rcu/tree.c:1639 [inline]
 rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1799
 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: 8678 Comm: syz-fuzzer Not tainted 5.3.0-rc5-next-20190820 #69
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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:2795 [inline]
 rcu_sched_clock_irq.cold+0x4fd/0xc0a kernel/rcu/tree.c:2244
 update_process_times+0x32/0x80 kernel/time/timer.c:1724
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1299
 __run_hrtimer kernel/time/hrtimer.c:1493 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1555
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1617
 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:830
 </IRQ>
RIP: 0010:do_user_addr_fault arch/x86/mm/fault.c:1339 [inline]
RIP: 0010:__do_page_fault+0x842/0xdd0 arch/x86/mm/fault.c:1506
Code: ff df 48 c1 e8 03 80 3c 10 00 0f 85 ab 04 00 00 48 83 3d 70 a3 c0 07 00 0f 84 8f 03 00 00 e8 f5 de 3f 00 fb 66 0f 1f 44 00 00 <c7> 45 c0 54 00 00 00 e9 4e fa ff ff e8 dd de 3f 00 48 8b 45 c8 48
RSP: 0000:ffff88808ceafea0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff88808db7c140 RBX: 00007f3b1eaa9000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8132508b RDI: ffff88808db7c9d4
RBP: ffff88808ceaff10 R08: ffff88808db7c140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00007f3b1eaa9000
R13: 0000000000000006 R14: ffff88808ceaff58 R15: ffff88808ceaffe0
 do_page_fault+0x38/0x590 arch/x86/mm/fault.c:1530
 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1202
RIP: 0033:0x45cfa3
Code: 00 48 81 eb 00 01 00 00 48 81 c7 00 01 00 00 48 81 fb 00 01 00 00 73 82 e9 07 ff ff ff c5 fd ef c0 48 81 fb 00 00 00 02 73 46 <c5> fe 7f 07 c5 fe 7f 47 20 c5 fe 7f 47 40 c5 fe 7f 47 60 48 81 eb
RSP: 002b:000000c420147dd8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000009000 RCX: 00007f3b1eab2000
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 00007f3b1eaa9000
RBP: 000000c420147e08 R08: 0000000007ffffff R09: ffffffffffffffff
R10: 0000000000000020 R11: 0000000000000000 R12: 000000c4217a5800
R13: 0000000000000045 R14: 000000000045b6a0 R15: 0000000000000000