rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10501 ticks this GP) idle=366/1/0x4000000000000002 softirq=304680/304680 fqs=0 
	(t=10502 jiffies g=601921 q=925)
rcu: rcu_preempt kthread starved for 10503 jiffies! g601921 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29056    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:2818 [inline]
 __schedule+0x7cb/0x1560 kernel/sched/core.c:3445
 schedule+0xa8/0x260 kernel/sched/core.c:3509
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807
 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline]
 rcu_gp_kthread+0x9b2/0x18b0 kernel/rcu/tree.c:1746
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 25063 Comm: syz-executor.3 Not tainted 5.2.0-rc2+ #35
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+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:2625 [inline]
 rcu_sched_clock_irq.cold+0x4d1/0xbfd kernel/rcu/tree.c:2161
 update_process_times+0x32/0x80 kernel/time/timer.c:1639
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1298
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33b/0xdd0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1066
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:920 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0x65/0x130 kernel/rcu/tree.c:911
Code: c3 40 5e 03 00 48 ba 00 00 00 00 00 fc ff df 89 c0 48 8d 3c c5 60 f2 74 88 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 9d 00 00 00 <48> 03 1c c5 60 f2 74 88 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 18
RSP: 0018:ffff888092f7f460 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: 0000000000035e40 RCX: 1ffffffff10e9e4c
RDX: dffffc0000000000 RSI: ffffffff833551ec RDI: ffffffff8874f260
RBP: ffff888092f7f478 R08: ffff8880a99ca500 R09: ffffed1015d06be0
R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: dffffc0000000000
R13: 000000000000000a R14: ffff888092f7f840 R15: 0000000000000000
 rcu_read_lock_held+0x8a/0xd0 kernel/rcu/update.c:268
 xfrm_sk_policy_lookup+0x329/0x510 net/xfrm/xfrm_policy.c:2162
 xfrm_lookup_with_ifid+0x1de/0x2070 net/xfrm/xfrm_policy.c:3036
 xfrm_lookup net/xfrm/xfrm_policy.c:3173 [inline]
 xfrm_lookup_route+0x3b/0x1f0 net/xfrm/xfrm_policy.c:3184
 ip6_dst_lookup_flow+0x189/0x220 net/ipv6/ip6_output.c:1096
 inet6_csk_route_socket+0x85d/0xf40 net/ipv6/inet6_connection_sock.c:106
 inet6_csk_xmit+0x110/0x5d0 net/ipv6/inet6_connection_sock.c:121
 l2tp_xmit_core net/l2tp/l2tp_core.c:1033 [inline]
 l2tp_xmit_skb+0x1112/0x13e0 net/l2tp/l2tp_core.c:1135
 pppol2tp_sendmsg+0x4a2/0x6b0 net/l2tp/l2tp_ppp.c:325
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:665
 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2286
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2381
 __do_sys_sendmmsg net/socket.c:2410 [inline]
 __se_sys_sendmmsg net/socket.c:2407 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2407
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459279
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:00007f05a8901c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459279
RDX: 0800000000000059 RSI: 0000000020005fc0 RDI: 0000000000000007
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f05a89026d4
R13: 00000000004c65fc R14: 00000000004db280 R15: 00000000ffffffff