INFO: rcu_preempt self-detected stall on CPU
	1-...: (1 GPs behind) idle=85a/140000000000002/0 softirq=116546/116547 fqs=28 
	 (t=10500 jiffies g=32648 c=32647 q=249)
rcu_preempt kthread starved for 701 jiffies! g32648 c32647 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=0
rcu_preempt     I29376     8      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_timeout+0x4df/0xe50 kernel/time/timer.c:1746
 rcu_gp_kthread+0xb3d/0x1ce0 kernel/rcu/tree.c:2255
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
NMI backtrace for cpu 1
CPU: 1 PID: 15478 Comm: syz-executor.5 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:158 [inline]
 rcu_dump_cpu_stacks+0x16d/0x1b8 kernel/rcu/tree.c:1396
 print_cpu_stall kernel/rcu/tree.c:1542 [inline]
 check_cpu_stall kernel/rcu/tree.c:1610 [inline]
 __rcu_pending kernel/rcu/tree.c:3390 [inline]
 rcu_pending kernel/rcu/tree.c:3452 [inline]
 rcu_check_callbacks.cold+0x490/0xdaa kernel/rcu/tree.c:2792
 update_process_times+0x29/0x60 kernel/time/timer.c:1590
 tick_sched_handle.isra.0+0x73/0x150 kernel/time/tick-sched.c:165
 tick_sched_timer+0x41/0x120 kernel/time/tick-sched.c:1223
 __run_hrtimer kernel/time/hrtimer.c:1223 [inline]
 __hrtimer_run_queues+0x24b/0xb90 kernel/time/hrtimer.c:1287
 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
 smp_apic_timer_interrupt+0x117/0x5f0 arch/x86/kernel/apic/apic.c:1100
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:66
RSP: 0018:ffff8880aed07790 EFLAGS: 00010246 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000000 RBX: 0000000001088020 RCX: 0000000000000240
RDX: 0000000000000400 RSI: 0000000000000000 RDI: ffff888094264200
RBP: 00000000000002c0 R08: 0000000000000000 R09: ffff888094264040
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888094264040
R13: ffff8880aa800ac0 R14: 0000000001088020 R15: ffff8880aa800ac0
 slab_alloc mm/slab.c:3388 [inline]
 __do_kmalloc mm/slab.c:3718 [inline]
 __kmalloc+0x39a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 neigh_alloc net/core/neighbour.c:324 [inline]
 __neigh_create+0x1da/0x1980 net/core/neighbour.c:499
 ip6_finish_output2+0x869/0x21b0 net/ipv6/ip6_output.c:117
 ip6_finish_output+0x702/0xaf0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:239 [inline]
 ip6_output+0x1c5/0x660 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:462 [inline]
 NF_HOOK include/linux/netfilter.h:250 [inline]
 ndisc_send_skb+0x88b/0x1390 net/ipv6/ndisc.c:483
 ndisc_send_rs+0x125/0x630 net/ipv6/ndisc.c:677
 addrconf_rs_timer+0x280/0x5a0 net/ipv6/addrconf.c:3765
 call_timer_fn+0x14a/0x650 kernel/time/timer.c:1279
 expire_timers+0x233/0x4d0 kernel/time/timer.c:1318
 __run_timers kernel/time/timer.c:1636 [inline]
 run_timer_softirq+0x1d8/0x5b0 kernel/time/timer.c:1649
 __do_softirq+0x254/0x9bf kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x15b/0x1a0 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:648 [inline]
 smp_apic_timer_interrupt+0x141/0x5f0 arch/x86/kernel/apic/apic.c:1102
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:779 [inline]
RIP: 0010:lock_acquire+0x1ec/0x3f0 kernel/locking/lockdep.c:4001
RSP: 0018:ffff88803fb37918 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff0f62cd1 RBX: ffff888095208240 RCX: ffff888095208ac8
RDX: dffffc0000000000 RSI: ffff888095208af0 RDI: 0000000000000282
RBP: ffff888083eaced8 R08: 00000000000025d8 R09: ffffffff89e68840
R10: ffff888095208af0 R11: ffff888095208240 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:152
 spin_lock include/linux/spinlock.h:317 [inline]
 d_walk+0x171/0x840 fs/dcache.c:1233
 kill_litter_super+0x3c/0x90 fs/super.c:1015
 deactivate_locked_super+0x6c/0xd0 fs/super.c:319
 deactivate_super fs/super.c:350 [inline]
 deactivate_super+0x7f/0xa0 fs/super.c:346
 cleanup_mnt+0xad/0x140 fs/namespace.c:1183
 mntput_no_expire+0x6b1/0x800 fs/namespace.c:1262
 mntput fs/namespace.c:1272 [inline]
 create_mnt_ns fs/namespace.c:3037 [inline]
 kern_unmount+0x98/0xc0 fs/namespace.c:3027
 put_ipc_ns ipc/namespace.c:163 [inline]
 put_ipc_ns+0x47/0x140 ipc/namespace.c:158
 free_nsproxy+0xbd/0x1f0 kernel/nsproxy.c:180
 switch_task_namespaces+0x8f/0xb0 kernel/nsproxy.c:229
 do_exit+0x9f6/0x2ae0 kernel/exit.c:857
 do_group_exit+0x100/0x2e0 kernel/exit.c:955
 get_signal+0x385/0x1c90 kernel/signal.c:2423
 do_signal+0x7c/0x15d0 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45cb19
RSP: 002b:00007f73fe2e1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: 0000000000000004 RBX: 00000000004db200 RCX: 000000000045cb19
RDX: 0000000000000048 RSI: 00000000200054c0 RDI: 0000000000000005
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000070 R14: 00000000004c3430 R15: 00007f73fe2e26d4