rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10499 ticks this GP) idle=f02/1/0x4000000000000002 softirq=169565/169565 fqs=5246 
rcu: 	 (t=10500 jiffies g=246653 q=184)
NMI backtrace for cpu 0
CPU: 0 PID: 22822 Comm: syz-executor3 Not tainted 4.20.0-rc7+ #382
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+0x1d3/0x2c6 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1c2/0x22c 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+0x16f/0x1bc kernel/rcu/tree.c:1195
 print_cpu_stall.cold.65+0x1f3/0x3c6 kernel/rcu/tree.c:1334
 check_cpu_stall kernel/rcu/tree.c:1408 [inline]
 rcu_pending kernel/rcu/tree.c:2961 [inline]
 rcu_check_callbacks+0xac1/0x1410 kernel/rcu/tree.c:2506
 update_process_times+0x2d/0x70 kernel/time/timer.c:1636
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1034 [inline]
 smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1059
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:debug_lockdep_rcu_enabled kernel/rcu/update.c:248 [inline]
RIP: 0010:rcu_read_lock_held+0x0/0xc0 kernel/rcu/update.c:275
Code: f6 9f 59 00 e9 00 f2 ff ff 48 c7 c7 f4 8d 16 8a e8 e5 9f 59 00 e9 1e ed ff ff e8 9b a0 59 00 e9 42 ea ff ff 66 0f 1f 44 00 00 <48> c7 c7 e4 5c 16 8a 55 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48
RSP: 0018:ffff8881bfc96f18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: ffff888196264480 RCX: ffffc90006401000
RDX: 0000000000040000 RSI: ffffffff86c9c899 RDI: 0000000000000001
RBP: ffff8881bfc96fe8 R08: ffff888134820340 R09: ffffed1032c4c89c
R10: ffffed1032c4c89c R11: ffff8881962644e3 R12: dffffc0000000000
R13: ffffed1037f92df0 R14: 0000000000000000 R15: ffff8881bfc976a0
 xfrm_lookup_with_ifid+0x2a1/0x2b80 net/xfrm/xfrm_policy.c:2063
 xfrm_lookup net/xfrm/xfrm_policy.c:2200 [inline]
 xfrm_lookup_route+0x3c/0x1f0 net/xfrm/xfrm_policy.c:2211
 ip6_dst_lookup_flow+0x1c6/0x270 net/ipv6/ip6_output.c:1084
 inet6_csk_route_socket+0x8bd/0x1020 net/ipv6/inet6_connection_sock.c:110
 inet6_csk_xmit+0x118/0x630 net/ipv6/inet6_connection_sock.c:125
 l2tp_xmit_core net/l2tp/l2tp_core.c:1030 [inline]
 l2tp_xmit_skb+0x134c/0x1670 net/l2tp/l2tp_core.c:1132
 pppol2tp_sendmsg+0x4b1/0x6c0 net/l2tp/l2tp_ppp.c:329
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:631
 ___sys_sendmsg+0x51d/0x930 net/socket.c:2116
 __sys_sendmmsg+0x246/0x6d0 net/socket.c:2211
 __do_sys_sendmmsg net/socket.c:2240 [inline]
 __se_sys_sendmmsg net/socket.c:2237 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2237
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457669
Code: fd b3 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f3706dc5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457669
RDX: 0800000000000059 RSI: 0000000020005fc0 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3706dc66d4
R13: 00000000004c3e4b R14: 00000000004d6ca8 R15: 00000000ffffffff