rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=976/1/0x4000000000000004 softirq=18578/18579 fqs=0 
	(t=29996 jiffies g=23201 q=246)
rcu: rcu_preempt kthread starved for 29996 jiffies! g23201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29112    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: 12384 Comm: syz-executor.5 Not tainted 5.2.0-next-20190718 #41
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: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 20 f1 d2 88 48 c1 e8 03 42 80 3c 30 00 0f 85 b1 06 00 00 48 83 3d 06 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: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a5e24 RBX: ffff88805f2ae5c0 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffff88805f2aee80 RDI: ffff88805f2aee54
RBP: ffff8880ae909f98 R08: 1ffffffff14a7d57 R09: fffffbfff14a7d58
R10: fffffbfff14a7d57 R11: ffffffff8a53eabf R12: ffff888099e478f8
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:arch_local_irq_restore /./arch/x86/include/asm/paravirt.h:767 [inline]
RIP: 0010:lock_acquire+0x20b/0x410 /kernel/locking/lockdep.c:4416
Code: 94 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 d3 01 00 00 48 83 3d 21 1a 7a 07 00 0f 84 53 01 00 00 48 8b 7d c8 57 9d <0f> 1f 44 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 65 8b
RSP: 0018:ffff888099e479a0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffffd7
RAX: 1ffffffff11a5e22 RBX: ffff88805f2ae5c0 RCX: ffffffff815879c2
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: 0000000000000282
RBP: ffff888099e479e8 R08: 1ffffffff14a7d57 R09: fffffbfff14a7d58
R10: ffff88805f2aee80 R11: ffff88805f2ae5c0 R12: ffffc900135d6dc0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
 rcu_lock_acquire /./include/linux/rcupdate.h:208 [inline]
 srcu_read_lock /./include/linux/srcu.h:155 [inline]
 vcpu_enter_guest+0x2597/0x5ec0 /arch/x86/kvm/x86.c:7978
 vcpu_run /arch/x86/kvm/x86.c:8145 [inline]
 kvm_arch_vcpu_ioctl_run+0x463/0x1790 /arch/x86/kvm/x86.c:8353
 kvm_vcpu_ioctl+0x4dc/0xfc0 /arch/x86/kvm/../../../virt/kvm/kvm_main.c:2752
 vfs_ioctl /fs/ioctl.c:46 [inline]
 file_ioctl /fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xdb6/0x13e0 /fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 /fs/ioctl.c:713
 __do_sys_ioctl /fs/ioctl.c:720 [inline]
 __se_sys_ioctl /fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 /fs/ioctl.c:718
 do_syscall_64+0xfd/0x6a0 /arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459819
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6de1890c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000008
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6de18916d4
R13: 00000000004c2bb7 R14: 00000000004d5f98 R15: 00000000ffffffff