rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10499 ticks this GP) idle=46e/1/0x4000000000000002 softirq=38930/38936 fqs=5243 
rcu: 	 (t=10500 jiffies g=43461 q=1288)
NMI backtrace for cpu 0
CPU: 0 PID: 20919 Comm: syz-executor.0 Not tainted 5.1.0-rc4+ #136
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.c:1223
 print_cpu_stall kernel/rcu/tree.c:1360 [inline]
 check_cpu_stall kernel/rcu/tree.c:1434 [inline]
 rcu_pending kernel/rcu/tree.c:3103 [inline]
 rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:xfrm_sk_policy_lookup+0x2cd/0x510 net/xfrm/xfrm_policy.c:2157
Code: c0 00 00 00 e8 e4 b6 64 fb 48 8d 7b 60 e8 0b f9 24 fd 31 ff 89 c3 89 c6 e8 10 b8 64 fb 84 db 0f 85 c9 00 00 00 e8 c3 b6 64 fb <48> 8b 45 a8 80 38 00 0f 85 d5 01 00 00 48 8b 45 b0 48 8b 18 48 89
RSP: 0018:ffff8880683f7498 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc90005e03000
RDX: 0000000000040000 RSI: ffffffff860bd83d RDI: 0000000000000001
RBP: ffff8880683f7500 R08: ffff88809ffb0000 R09: ffffed101486f49d
R10: ffffed101486f49c R11: ffff8880a437a4e3 R12: dffffc0000000000
R13: 000000000000000a R14: ffff8880683f7840 R15: 0000000000000000
 xfrm_lookup_with_ifid+0x1de/0x1ce0 net/xfrm/xfrm_policy.c:3038
 xfrm_lookup net/xfrm/xfrm_policy.c:3175 [inline]
 xfrm_lookup_route+0x3b/0x1f0 net/xfrm/xfrm_policy.c:3186
 ip6_dst_lookup_flow+0x189/0x220 net/ipv6/ip6_output.c:1100
 inet6_csk_route_socket+0x85d/0xf40 net/ipv6/inet6_connection_sock.c:110
 inet6_csk_xmit+0x110/0x5d0 net/ipv6/inet6_connection_sock.c:125
 l2tp_xmit_core net/l2tp/l2tp_core.c:1033 [inline]
 l2tp_xmit_skb+0x1114/0x13e0 net/l2tp/l2tp_core.c:1135
 pppol2tp_sendmsg+0x4a2/0x6b0 net/l2tp/l2tp_ppp.c:329
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:661
 ___sys_sendmsg+0x3e2/0x930 net/socket.c:2260
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2355
 __do_sys_sendmmsg net/socket.c:2384 [inline]
 __se_sys_sendmmsg net/socket.c:2381 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2381
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458c29
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fbf35578c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458c29
RDX: 000000000000028e RSI: 0000000020005fc0 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbf355796d4
R13: 00000000004c5e19 R14: 00000000004da5e0 R15: 00000000ffffffff